diff --git a/mobile/android/app/src/main/kotlin/app/alextran/immich/images/LocalImagesImpl.kt b/mobile/android/app/src/main/kotlin/app/alextran/immich/images/LocalImagesImpl.kt
index 0de194024d..d6dbf22f31 100644
--- a/mobile/android/app/src/main/kotlin/app/alextran/immich/images/LocalImagesImpl.kt
+++ b/mobile/android/app/src/main/kotlin/app/alextran/immich/images/LocalImagesImpl.kt
@@ -33,6 +33,7 @@ data class Request(
   val callback: (Result<Map<String, Long>?>) -> Unit
 )
 
+/** Set [exactSize] to decode at the smallest size that covers [target] without upscaling. */
 @RequiresApi(Build.VERSION_CODES.Q)
 inline fun ImageDecoder.Source.decodeBitmap(target: Size = Size(0, 0), exactSize: Boolean = false): Bitmap {
   return ImageDecoder.decodeBitmap(this) { decoder, info, _ ->
diff --git a/mobile/android/app/src/main/kotlin/app/alextran/immich/images/RemoteImages.g.kt b/mobile/android/app/src/main/kotlin/app/alextran/immich/images/RemoteImages.g.kt
index d0a377a634..f3b61adcd9 100644
--- a/mobile/android/app/src/main/kotlin/app/alextran/immich/images/RemoteImages.g.kt
+++ b/mobile/android/app/src/main/kotlin/app/alextran/immich/images/RemoteImages.g.kt
@@ -47,7 +47,8 @@ private open class RemoteImagesPigeonCodec : StandardMessageCodec() {
 
 /** Generated interface from Pigeon that represents a handler of messages from Flutter. */
 interface RemoteImageApi {
-  fun requestImage(url: String, requestId: Long, preferEncoded: Boolean, width: Long, height: Long, callback: (Result<Map<String, Long>?>) -> Unit)
+  /** Width and height are the physical decode size, or null for the source size. */
+  fun requestImage(url: String, requestId: Long, preferEncoded: Boolean, width: Long?, height: Long?, callback: (Result<Map<String, Long>?>) -> Unit)
   fun cancelRequest(requestId: Long)
   fun clearCache(callback: (Result<Long>) -> Unit)
 
@@ -68,8 +69,8 @@ interface RemoteImageApi {
             val urlArg = args[0] as String
             val requestIdArg = args[1] as Long
             val preferEncodedArg = args[2] as Boolean
-            val widthArg = args[3] as Long
-            val heightArg = args[4] as Long
+            val widthArg = args[3] as Long?
+            val heightArg = args[4] as Long?
             api.requestImage(urlArg, requestIdArg, preferEncodedArg, widthArg, heightArg) { result: Result<Map<String, Long>?> ->
               val error = result.exceptionOrNull()
               if (error != null) {
diff --git a/mobile/android/app/src/main/kotlin/app/alextran/immich/images/RemoteImagesImpl.kt b/mobile/android/app/src/main/kotlin/app/alextran/immich/images/RemoteImagesImpl.kt
index 148cdeb929..cdc82c871c 100644
--- a/mobile/android/app/src/main/kotlin/app/alextran/immich/images/RemoteImagesImpl.kt
+++ b/mobile/android/app/src/main/kotlin/app/alextran/immich/images/RemoteImagesImpl.kt
@@ -80,8 +80,8 @@ class RemoteImagesImpl(context: Context) : RemoteImageApi {
     url: String,
     requestId: Long,
     preferEncoded: Boolean,
-    width: Long,
-    height: Long,
+    width: Long?,
+    height: Long?,
     callback: (Result<Map<String, Long>?>) -> Unit
   ) {
     val signal = CancellationSignal()
@@ -105,15 +105,21 @@ class RemoteImagesImpl(context: Context) : RemoteImageApi {
         if (!preferEncoded && Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
           decodeExecutor.execute {
             val res = if (signal.isCanceled) null else try {
-              val source = ImageDecoder.createSource(NativeBuffer.wrap(buffer.pointer, buffer.offset))
-              val target = Size(width.toInt(), height.toInt())
-              val bitmap = source.decodeBitmap(target, exactSize = true)
               // The embedded preview a raw decodes to has no orientation, so read the container's.
               val orientation = if (isRawMime(contentType)) {
                 readRawOrientation(NativeBuffer.wrap(buffer.pointer, buffer.offset), buffer.offset)
               } else {
                 ExifInterface.ORIENTATION_NORMAL
               }
+              val target = when (orientation) {
+                ExifInterface.ORIENTATION_TRANSPOSE,
+                ExifInterface.ORIENTATION_ROTATE_90,
+                ExifInterface.ORIENTATION_TRANSVERSE,
+                ExifInterface.ORIENTATION_ROTATE_270 -> Size(height?.toInt() ?: 0, width?.toInt() ?: 0)
+                else -> Size(width?.toInt() ?: 0, height?.toInt() ?: 0)
+              }
+              val source = ImageDecoder.createSource(NativeBuffer.wrap(buffer.pointer, buffer.offset))
+              val bitmap = source.decodeBitmap(target, exactSize = true)
               if (orientation == ExifInterface.ORIENTATION_NORMAL || orientation == ExifInterface.ORIENTATION_UNDEFINED) {
                 bitmap.toNativeBuffer()
               } else {
diff --git a/mobile/ios/Runner/Images/RemoteImages.g.swift b/mobile/ios/Runner/Images/RemoteImages.g.swift
index eb1bf01b13..238aeca2db 100644
--- a/mobile/ios/Runner/Images/RemoteImages.g.swift
+++ b/mobile/ios/Runner/Images/RemoteImages.g.swift
@@ -70,7 +70,8 @@ class RemoteImagesPigeonCodec: FlutterStandardMessageCodec, @unchecked Sendable
 
 /// Generated protocol from Pigeon that represents a handler of messages from Flutter.
 protocol RemoteImageApi {
-  func requestImage(url: String, requestId: Int64, preferEncoded: Bool, width: Int64, height: Int64, completion: @escaping (Result<[String: Int64]?, Error>) -> Void)
+  /// Width and height are the physical decode size, or null for the source size.
+  func requestImage(url: String, requestId: Int64, preferEncoded: Bool, width: Int64?, height: Int64?, completion: @escaping (Result<[String: Int64]?, Error>) -> Void)
   func cancelRequest(requestId: Int64) throws
   func clearCache(completion: @escaping (Result<Int64, Error>) -> Void)
 }
@@ -81,6 +82,7 @@ class RemoteImageApiSetup {
   /// Sets up an instance of `RemoteImageApi` to handle messages through the `binaryMessenger`.
   static func setUp(binaryMessenger: FlutterBinaryMessenger, api: RemoteImageApi?, messageChannelSuffix: String = "") {
     let channelSuffix = messageChannelSuffix.count > 0 ? ".\(messageChannelSuffix)" : ""
+    /// Width and height are the physical decode size, or null for the source size.
     let requestImageChannel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.immich_mobile.RemoteImageApi.requestImage\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec)
     if let api = api {
       requestImageChannel.setMessageHandler { message, reply in
@@ -88,8 +90,8 @@ class RemoteImageApiSetup {
         let urlArg = args[0] as! String
         let requestIdArg = args[1] as! Int64
         let preferEncodedArg = args[2] as! Bool
-        let widthArg = args[3] as! Int64
-        let heightArg = args[4] as! Int64
+        let widthArg: Int64? = nilOrValue(args[3])
+        let heightArg: Int64? = nilOrValue(args[4])
         api.requestImage(url: urlArg, requestId: requestIdArg, preferEncoded: preferEncodedArg, width: widthArg, height: heightArg) { result in
           switch result {
           case .success(let res):
diff --git a/mobile/ios/Runner/Images/RemoteImagesImpl.swift b/mobile/ios/Runner/Images/RemoteImagesImpl.swift
index b7de76cb86..d6b2ce1b09 100644
--- a/mobile/ios/Runner/Images/RemoteImagesImpl.swift
+++ b/mobile/ios/Runner/Images/RemoteImagesImpl.swift
@@ -35,7 +35,7 @@ class RemoteImageApiImpl: NSObject, RemoteImageApi {
     kCGImageSourceCreateThumbnailFromImageAlways: true
   ]
 
-  func requestImage(url: String, requestId: Int64, preferEncoded: Bool, width: Int64, height: Int64, completion: @escaping (Result<[String : Int64]?, any Error>) -> Void) {
+  func requestImage(url: String, requestId: Int64, preferEncoded: Bool, width: Int64?, height: Int64?, completion: @escaping (Result<[String : Int64]?, any Error>) -> Void) {
     var urlRequest = URLRequest(url: URL(string: url)!)
     urlRequest.cachePolicy = .returnCacheDataElseLoad
 
@@ -50,7 +50,7 @@ class RemoteImageApiImpl: NSObject, RemoteImageApi {
     task.resume()
   }
 
-  private static func handleCompletion(request: RemoteImageRequest, encoded: Bool, width: Int64, height: Int64, data: Data?, response: URLResponse?, error: Error?) {
+  private static func handleCompletion(request: RemoteImageRequest, encoded: Bool, width: Int64?, height: Int64?, data: Data?, response: URLResponse?, error: Error?) {
     if request.isCancelled {
       return request.completion(ImageProcessing.cancelledResult)
     }
@@ -94,7 +94,7 @@ class RemoteImageApiImpl: NSObject, RemoteImageApi {
       }
 
       var options = decodeOptions
-      if let maxPixelSize = targetMaxPixelSize(imageSource: imageSource, width: width, height: height) {
+      if let maxPixelSize = targetThumbnailRenderSize(imageSource: imageSource, width: width, height: height) {
         options[kCGImageSourceThumbnailMaxPixelSize] = maxPixelSize
       }
 
@@ -130,8 +130,11 @@ class RemoteImageApiImpl: NSObject, RemoteImageApi {
     }
   }
 
-  private static func targetMaxPixelSize(imageSource: CGImageSource, width: Int64, height: Int64) -> Int? {
-    guard width > 0,
+  /// Returns the longest rendered edge needed to cover the requested size.
+  private static func targetThumbnailRenderSize(imageSource: CGImageSource, width: Int64?, height: Int64?) -> Int? {
+    guard let width,
+          let height,
+          width > 0,
           height > 0,
           let properties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, nil) as? [CFString: Any],
           let pixelWidth = properties[kCGImagePropertyPixelWidth] as? NSNumber,
@@ -139,9 +142,17 @@ class RemoteImageApiImpl: NSObject, RemoteImageApi {
       return nil
     }
 
-    let orientation = (properties[kCGImagePropertyOrientation] as? NSNumber)?.intValue ?? 1
-    let sourceWidth = (5...8).contains(orientation) ? pixelHeight.doubleValue : pixelWidth.doubleValue
-    let sourceHeight = (5...8).contains(orientation) ? pixelWidth.doubleValue : pixelHeight.doubleValue
+    let orientation = (properties[kCGImagePropertyOrientation] as? NSNumber)
+      .flatMap { CGImagePropertyOrientation(rawValue: $0.uint32Value) } ?? .up
+    let swapsDimensions: Bool
+    switch orientation {
+    case .leftMirrored, .right, .rightMirrored, .left:
+      swapsDimensions = true
+    default:
+      swapsDimensions = false
+    }
+    let sourceWidth = swapsDimensions ? pixelHeight.doubleValue : pixelWidth.doubleValue
+    let sourceHeight = swapsDimensions ? pixelWidth.doubleValue : pixelHeight.doubleValue
     let fillScale = max(Double(width) / sourceWidth, Double(height) / sourceHeight)
     let scale = min(1, fillScale)
     return scale < 1 ? Int(ceil(max(sourceWidth * scale, sourceHeight * scale))) : nil
diff --git a/mobile/lib/infrastructure/loaders/image_request.dart b/mobile/lib/infrastructure/loaders/image_request.dart
index 1a0075d93a..bbbbbef72d 100644
--- a/mobile/lib/infrastructure/loaders/image_request.dart
+++ b/mobile/lib/infrastructure/loaders/image_request.dart
@@ -40,7 +40,7 @@ abstract class ImageRequest {
   Future<(ui.Codec, ui.ImageDescriptor)?> _codecFromEncodedPlatformImage(
     int address,
     int length, {
-    ui.Size size = ui.Size.zero,
+    ui.Size? size,
   }) async {
     final pointer = Pointer<Uint8>.fromAddress(address);
     if (_isCancelled) {
@@ -78,7 +78,7 @@ abstract class ImageRequest {
     return (codec, descriptor);
   }
 
-  Future<ui.FrameInfo?> _fromEncodedPlatformImage(int address, int length, {ui.Size size = ui.Size.zero}) async {
+  Future<ui.FrameInfo?> _fromEncodedPlatformImage(int address, int length, {ui.Size? size}) async {
     final result = await _codecFromEncodedPlatformImage(address, length, size: size);
     if (result == null) {
       return null;
@@ -102,8 +102,8 @@ abstract class ImageRequest {
     return frame;
   }
 
-  (int, int)? _targetSize(int width, int height, ui.Size size) {
-    if (size.width <= 0 || size.height <= 0) {
+  (int, int)? _targetSize(int width, int height, ui.Size? size) {
+    if (size == null || size.width <= 0 || size.height <= 0) {
       return null;
     }
 
diff --git a/mobile/lib/infrastructure/loaders/remote_image_request.dart b/mobile/lib/infrastructure/loaders/remote_image_request.dart
index 6827bc76e2..4e2ad89d10 100644
--- a/mobile/lib/infrastructure/loaders/remote_image_request.dart
+++ b/mobile/lib/infrastructure/loaders/remote_image_request.dart
@@ -2,9 +2,11 @@ part of 'image_request.dart';
 
 class RemoteImageRequest extends ImageRequest {
   final String uri;
-  final ui.Size size;
 
-  RemoteImageRequest({required this.uri, this.size = ui.Size.zero});
+  /// Physical size to decode, or null for the source size.
+  final ui.Size? size;
+
+  RemoteImageRequest({required this.uri, this.size});
 
   @override
   Future<ImageInfo?> load(ImageDecoderCallback decode, {double scale = 1.0}) async {
@@ -16,8 +18,8 @@ class RemoteImageRequest extends ImageRequest {
       uri,
       requestId: requestId,
       preferEncoded: false,
-      width: size.width.ceil(),
-      height: size.height.ceil(),
+      width: size?.width.ceil(),
+      height: size?.height.ceil(),
     );
     // Android falls back to encoded data if native decoding fails, so check for both shapes of the response.
     final frame = switch (info) {
@@ -35,7 +37,13 @@ class RemoteImageRequest extends ImageRequest {
       return null;
     }
 
-    final info = await remoteImageApi.requestImage(uri, requestId: requestId, preferEncoded: true, width: 0, height: 0);
+    final info = await remoteImageApi.requestImage(
+      uri,
+      requestId: requestId,
+      preferEncoded: true,
+      width: null,
+      height: null,
+    );
     if (info == null) {
       return null;
     }
diff --git a/mobile/lib/platform/remote_image_api.g.dart b/mobile/lib/platform/remote_image_api.g.dart
index 64d56bb882..f8a965356c 100644
--- a/mobile/lib/platform/remote_image_api.g.dart
+++ b/mobile/lib/platform/remote_image_api.g.dart
@@ -60,12 +60,13 @@ class RemoteImageApi {
 
   final String pigeonVar_messageChannelSuffix;
 
+  /// Width and height are the physical decode size, or null for the source size.
   Future<Map<String, int>?> requestImage(
     String url, {
     required int requestId,
     required bool preferEncoded,
-    required int width,
-    required int height,
+    int? width,
+    int? height,
   }) async {
     final pigeonVar_channelName =
         'dev.flutter.pigeon.immich_mobile.RemoteImageApi.requestImage$pigeonVar_messageChannelSuffix';
diff --git a/mobile/lib/presentation/widgets/asset_viewer/asset_page.widget.dart b/mobile/lib/presentation/widgets/asset_viewer/asset_page.widget.dart
index 92633661b8..faf03b7f20 100644
--- a/mobile/lib/presentation/widgets/asset_viewer/asset_page.widget.dart
+++ b/mobile/lib/presentation/widgets/asset_viewer/asset_page.widget.dart
@@ -403,8 +403,8 @@ class _AssetPageState extends ConsumerState<AssetPage> {
 
   @override
   Widget build(BuildContext context) {
-    final (currentAsset, initialThumbnail) = ref.watch(
-      assetViewerProvider.select((s) => (s.currentAsset, s.initialThumbnail)),
+    final (currentAsset, thumbnailSize) = ref.watch(
+      assetViewerProvider.select((s) => (s.currentAsset, s.thumbnailSize)),
     );
     _showingDetails = ref.watch(assetViewerProvider.select((s) => s.showingDetails));
     final stackIndex = ref.watch(assetViewerProvider.select((s) => s.stackIndex));
@@ -461,7 +461,7 @@ class _AssetPageState extends ConsumerState<AssetPage> {
                     isCurrent: isCurrent,
                     isPlayingMotionVideo: isPlayingMotionVideo,
                     localFilePath: viewIntentFilePath,
-                    remoteThumbnailSize: initialThumbnail?.tag == displayAsset.heroTag ? initialThumbnail!.size : null,
+                    remoteThumbnailSize: thumbnailSize,
                   ),
                 ),
                 if (showingOcr && displayAsset.width != null && displayAsset.height != null)
diff --git a/mobile/lib/presentation/widgets/asset_viewer/asset_preloader.dart b/mobile/lib/presentation/widgets/asset_viewer/asset_preloader.dart
index 4d1856b90d..8c153e9995 100644
--- a/mobile/lib/presentation/widgets/asset_viewer/asset_preloader.dart
+++ b/mobile/lib/presentation/widgets/asset_viewer/asset_preloader.dart
@@ -17,7 +17,8 @@ class AssetPreloader {
 
   AssetPreloader({required this.timelineService, required this.mounted});
 
-  void preload(int index, Size size) {
+  /// Preloads adjacent images with the current thumbnail size.
+  void preload(int index, Size size, {Size? thumbnailSize}) {
     unawaited(timelineService.preloadAssets(index));
     _timer?.cancel();
     _timer = Timer(Durations.medium4, () async {
@@ -33,13 +34,14 @@ class AssetPreloader {
       }
       _prevStream?.removeListener(_dummyListener);
       _nextStream?.removeListener(_dummyListener);
-      _prevStream = prev != null ? _resolveImage(prev, size) : null;
-      _nextStream = next != null ? _resolveImage(next, size) : null;
+      _prevStream = prev != null ? _resolveImage(prev, size, thumbnailSize) : null;
+      _nextStream = next != null ? _resolveImage(next, size, thumbnailSize) : null;
     });
   }
 
-  ImageStream _resolveImage(BaseAsset asset, Size size) {
-    return getFullImageProvider(asset, size: size).resolve(ImageConfiguration.empty)..addListener(_dummyListener);
+  ImageStream _resolveImage(BaseAsset asset, Size size, Size? thumbnailSize) {
+    return getFullImageProvider(asset, size: size, remoteThumbnailSize: thumbnailSize).resolve(ImageConfiguration.empty)
+      ..addListener(_dummyListener);
   }
 
   void dispose() {
diff --git a/mobile/lib/presentation/widgets/asset_viewer/asset_viewer.page.dart b/mobile/lib/presentation/widgets/asset_viewer/asset_viewer.page.dart
index 558af8361f..39479b56c0 100644
--- a/mobile/lib/presentation/widgets/asset_viewer/asset_viewer.page.dart
+++ b/mobile/lib/presentation/widgets/asset_viewer/asset_viewer.page.dart
@@ -64,6 +64,7 @@ class AssetViewer extends ConsumerStatefulWidget {
   @override
   ConsumerState createState() => _AssetViewerState();
 
+  /// Sets the asset and thumbnail size before opening the viewer.
   static void setAsset(WidgetRef ref, BaseAsset asset, {Size? thumbnailSize}) {
     ref.read(assetViewerProvider.notifier).reset();
 
@@ -72,10 +73,6 @@ class AssetViewer extends ConsumerStatefulWidget {
       ref.read(assetViewerProvider.notifier).setControls(false);
     }
 
-    _setAsset(ref, asset, thumbnailSize: thumbnailSize);
-  }
-
-  static void _setAsset(WidgetRef ref, BaseAsset asset, {Size? thumbnailSize}) {
     ref.read(assetViewerProvider.notifier).setAsset(asset, thumbnailSize: thumbnailSize);
   }
 }
@@ -162,7 +159,11 @@ class _AssetViewerState extends ConsumerState<AssetViewer> {
   }
 
   void _onAssetInit(Duration timeStamp) {
-    _preloader.preload(widget.initialIndex, context.sizeData);
+    _preloader.preload(
+      widget.initialIndex,
+      context.sizeData,
+      thumbnailSize: ref.read(assetViewerProvider).thumbnailSize,
+    );
     _handleCasting();
   }
 
@@ -174,8 +175,8 @@ class _AssetViewerState extends ConsumerState<AssetViewer> {
       return;
     }
 
-    AssetViewer._setAsset(ref, asset);
-    _preloader.preload(index, context.sizeData);
+    ref.read(assetViewerProvider.notifier).setAsset(asset);
+    _preloader.preload(index, context.sizeData, thumbnailSize: ref.read(assetViewerProvider).thumbnailSize);
     _handleCasting();
     _stackChildrenKeepAlive?.close();
     _stackChildrenKeepAlive = ref.read(stackChildrenNotifier(asset).notifier).ref.keepAlive();
diff --git a/mobile/lib/presentation/widgets/images/image_provider.dart b/mobile/lib/presentation/widgets/images/image_provider.dart
index 8b46840c0a..05db05b80a 100644
--- a/mobile/lib/presentation/widgets/images/image_provider.dart
+++ b/mobile/lib/presentation/widgets/images/image_provider.dart
@@ -200,12 +200,7 @@ ImageProvider? getThumbnailImageProvider(
   final assetId = asset is RemoteAsset ? asset.id : (asset as LocalAsset).remoteId;
   final thumbhash = asset is RemoteAsset ? asset.thumbHash ?? "" : "";
   return assetId != null
-      ? RemoteImageProvider.thumbnail(
-          assetId: assetId,
-          thumbhash: thumbhash,
-          edited: edited,
-          size: remoteSize ?? Size.zero,
-        )
+      ? RemoteImageProvider.thumbnail(assetId: assetId, thumbhash: thumbhash, edited: edited, size: remoteSize)
       : null;
 }
 
diff --git a/mobile/lib/presentation/widgets/images/remote_image_provider.dart b/mobile/lib/presentation/widgets/images/remote_image_provider.dart
index 0a825aff7c..b2dbc32f01 100644
--- a/mobile/lib/presentation/widgets/images/remote_image_provider.dart
+++ b/mobile/lib/presentation/widgets/images/remote_image_provider.dart
@@ -13,16 +13,14 @@ class RemoteImageProvider extends CancellableImageProvider<RemoteImageProvider>
     with CancellableImageProviderMixin<RemoteImageProvider> {
   final String url;
   final bool edited;
-  final Size size;
 
-  RemoteImageProvider({required this.url, this.edited = true, this.size = Size.zero});
+  /// Physical size to decode, or null for the source size.
+  final Size? size;
 
-  RemoteImageProvider.thumbnail({
-    required String assetId,
-    required String thumbhash,
-    this.edited = true,
-    this.size = Size.zero,
-  }) : url = getThumbnailUrlForRemoteId(assetId, thumbhash: thumbhash, edited: edited);
+  RemoteImageProvider({required this.url, this.edited = true, this.size});
+
+  RemoteImageProvider.thumbnail({required String assetId, required String thumbhash, this.edited = true, this.size})
+    : url = getThumbnailUrlForRemoteId(assetId, thumbhash: thumbhash, edited: edited);
 
   @override
   Future<RemoteImageProvider> obtainKey(ImageConfiguration configuration) {
@@ -68,6 +66,8 @@ class RemoteFullImageProvider extends CancellableImageProvider<RemoteFullImagePr
   final AssetType assetType;
   final bool isAnimated;
   final bool edited;
+
+  /// Physical size of the thumbnail shown before the preview.
   final Size? thumbnailSize;
 
   RemoteFullImageProvider({
@@ -91,11 +91,7 @@ class RemoteFullImageProvider extends CancellableImageProvider<RemoteFullImagePr
         stream: _animatedCodec(key, decode),
         scale: 1.0,
         initialImage: getInitialImage(
-          RemoteImageProvider.thumbnail(
-            assetId: key.assetId,
-            thumbhash: key.thumbhash,
-            size: key.thumbnailSize ?? Size.zero,
-          ),
+          RemoteImageProvider.thumbnail(assetId: key.assetId, thumbhash: key.thumbhash, size: key.thumbnailSize),
         ),
         informationCollector: () => <DiagnosticsNode>[
           DiagnosticsProperty<ImageProvider>('Image provider', this),
@@ -113,7 +109,7 @@ class RemoteFullImageProvider extends CancellableImageProvider<RemoteFullImagePr
           assetId: key.assetId,
           thumbhash: key.thumbhash,
           edited: key.edited,
-          size: key.thumbnailSize ?? Size.zero,
+          size: key.thumbnailSize,
         ),
       ),
       informationCollector: () => <DiagnosticsNode>[
diff --git a/mobile/lib/presentation/widgets/images/thumbnail.widget.dart b/mobile/lib/presentation/widgets/images/thumbnail.widget.dart
index 535868b13e..1e549cd981 100644
--- a/mobile/lib/presentation/widgets/images/thumbnail.widget.dart
+++ b/mobile/lib/presentation/widgets/images/thumbnail.widget.dart
@@ -25,7 +25,9 @@ class Thumbnail extends StatefulWidget {
     required String remoteId,
     required String thumbhash,
     this.fit = BoxFit.cover,
-    Size size = Size.zero,
+
+    /// Physical size to decode, or null for the source size.
+    Size? size,
     super.key,
   }) : imageProvider = RemoteImageProvider.thumbnail(assetId: remoteId, thumbhash: thumbhash, size: size),
        thumbhashProvider = null;
@@ -33,9 +35,11 @@ class Thumbnail extends StatefulWidget {
   Thumbnail.fromAsset({
     required BaseAsset? asset,
     this.fit = BoxFit.cover,
+
+    /// Decode size for local thumbnails. This does not affect the widget size.
     Size size = kThumbnailResolution,
 
-    /// The physical decode size for remote thumbnails. This does not affect the widget size.
+    /// Physical size to decode for remote thumbnails.
     Size? remoteSize,
     super.key,
   }) : thumbhashProvider = switch (asset) {
diff --git a/mobile/lib/presentation/widgets/images/thumbnail_tile.widget.dart b/mobile/lib/presentation/widgets/images/thumbnail_tile.widget.dart
index c3b439f8cd..05f40e7903 100644
--- a/mobile/lib/presentation/widgets/images/thumbnail_tile.widget.dart
+++ b/mobile/lib/presentation/widgets/images/thumbnail_tile.widget.dart
@@ -27,6 +27,8 @@ class ThumbnailTile extends ConsumerStatefulWidget {
 
   final BaseAsset? asset;
   final Size size;
+
+  /// Physical size to decode for remote thumbnails.
   final Size? remoteSize;
   final BoxFit fit;
   final bool showStorageIndicator;
diff --git a/mobile/lib/presentation/widgets/timeline/constants.dart b/mobile/lib/presentation/widgets/timeline/constants.dart
index 35b61cfc52..86c44d4a7f 100644
--- a/mobile/lib/presentation/widgets/timeline/constants.dart
+++ b/mobile/lib/presentation/widgets/timeline/constants.dart
@@ -11,13 +11,3 @@ const Duration kTimelineScrubberFadeOutDuration = Duration(milliseconds: 800);
 
 const Size kThumbnailResolution = Size.square(320);
 const kThumbnailDiskCacheSize = 1024 << 20; // 1GiB
-
-Size getThumbnailResolution(Size size, double pixelRatio) {
-  final width = size.width * pixelRatio;
-  final height = size.height * pixelRatio;
-  if (!width.isFinite || !height.isFinite || width <= 0 || height <= 0) {
-    return Size.zero;
-  }
-
-  return Size(width.ceilToDouble(), height.ceilToDouble());
-}
diff --git a/mobile/lib/presentation/widgets/timeline/fixed/segment.model.dart b/mobile/lib/presentation/widgets/timeline/fixed/segment.model.dart
index 54bc7a448d..bc066e6ee3 100644
--- a/mobile/lib/presentation/widgets/timeline/fixed/segment.model.dart
+++ b/mobile/lib/presentation/widgets/timeline/fixed/segment.model.dart
@@ -10,7 +10,6 @@ import 'package:immich_mobile/domain/services/timeline.service.dart';
 import 'package:immich_mobile/extensions/build_context_extensions.dart';
 import 'package:immich_mobile/presentation/widgets/asset_viewer/asset_viewer.page.dart';
 import 'package:immich_mobile/presentation/widgets/images/thumbnail_tile.widget.dart';
-import 'package:immich_mobile/presentation/widgets/timeline/constants.dart';
 import 'package:immich_mobile/presentation/widgets/timeline/fixed/row.dart';
 import 'package:immich_mobile/presentation/widgets/timeline/header.widget.dart';
 import 'package:immich_mobile/presentation/widgets/timeline/segment.model.dart';
@@ -213,7 +212,7 @@ class _AssetTileWidget extends ConsumerWidget {
     int assetIndex,
     BaseAsset asset,
     int? heroOffset,
-    Size? remoteSize,
+    Size remoteSize,
   ) async {
     final multiSelectState = ref.read(multiSelectProvider);
 
@@ -262,8 +261,7 @@ class _AssetTileWidget extends ConsumerWidget {
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
-    final resolution = getThumbnailResolution(size, MediaQuery.devicePixelRatioOf(context));
-    final remoteSize = resolution == Size.zero ? null : resolution;
+    final remoteSize = size * MediaQuery.devicePixelRatioOf(context);
 
     final heroOffset = TabsRouterScope.of(context)?.controller.activeIndex ?? 0;
 
diff --git a/mobile/lib/providers/asset_viewer/asset_viewer.provider.dart b/mobile/lib/providers/asset_viewer/asset_viewer.provider.dart
index c65937139c..c3023ea248 100644
--- a/mobile/lib/providers/asset_viewer/asset_viewer.provider.dart
+++ b/mobile/lib/providers/asset_viewer/asset_viewer.provider.dart
@@ -13,7 +13,9 @@ class AssetViewerState {
   final bool isZoomed;
   final bool showingOcr;
   final BaseAsset? currentAsset;
-  final ({String tag, Size size})? initialThumbnail;
+
+  /// Physical thumbnail size retained while paging through the viewer.
+  final Size? thumbnailSize;
   final int stackIndex;
 
   const AssetViewerState({
@@ -23,7 +25,7 @@ class AssetViewerState {
     this.isZoomed = false,
     this.showingOcr = false,
     this.currentAsset,
-    this.initialThumbnail,
+    this.thumbnailSize,
     this.stackIndex = 0,
   });
 
@@ -34,7 +36,7 @@ class AssetViewerState {
     bool? isZoomed,
     bool? showingOcr,
     BaseAsset? currentAsset,
-    ({String tag, Size size})? initialThumbnail,
+    Size? thumbnailSize,
     int? stackIndex,
   }) {
     return AssetViewerState(
@@ -44,7 +46,7 @@ class AssetViewerState {
       isZoomed: isZoomed ?? this.isZoomed,
       showingOcr: showingOcr ?? this.showingOcr,
       currentAsset: currentAsset ?? this.currentAsset,
-      initialThumbnail: initialThumbnail ?? this.initialThumbnail,
+      thumbnailSize: thumbnailSize ?? this.thumbnailSize,
       stackIndex: stackIndex ?? this.stackIndex,
     );
   }
@@ -69,7 +71,7 @@ class AssetViewerState {
         other.isZoomed == isZoomed &&
         other.showingOcr == showingOcr &&
         other.currentAsset == currentAsset &&
-        other.initialThumbnail == initialThumbnail &&
+        other.thumbnailSize == thumbnailSize &&
         other.stackIndex == stackIndex;
   }
 
@@ -81,7 +83,7 @@ class AssetViewerState {
       isZoomed.hashCode ^
       showingOcr.hashCode ^
       currentAsset.hashCode ^
-      initialThumbnail.hashCode ^
+      thumbnailSize.hashCode ^
       stackIndex.hashCode;
 }
 
@@ -104,12 +106,7 @@ class AssetViewerStateNotifier extends Notifier<AssetViewerState> {
     if (asset == state.currentAsset) {
       return;
     }
-    state = state.copyWith(
-      currentAsset: asset,
-      initialThumbnail: thumbnailSize == null ? null : (tag: asset.heroTag, size: thumbnailSize),
-      stackIndex: 0,
-      showingOcr: false,
-    );
+    state = state.copyWith(currentAsset: asset, thumbnailSize: thumbnailSize, stackIndex: 0, showingOcr: false);
     _watchCurrentAsset(asset);
   }
 
diff --git a/mobile/pigeon/remote_image_api.dart b/mobile/pigeon/remote_image_api.dart
index bc2f96604c..277b7016fd 100644
--- a/mobile/pigeon/remote_image_api.dart
+++ b/mobile/pigeon/remote_image_api.dart
@@ -13,13 +13,14 @@ import 'package:pigeon/pigeon.dart';
 )
 @HostApi()
 abstract class RemoteImageApi {
+  /// Width and height are the physical decode size, or null for the source size.
   @async
   Map<String, int>? requestImage(
     String url, {
     required int requestId,
     required bool preferEncoded,
-    required int width,
-    required int height,
+    int? width,
+    int? height,
   });
 
   void cancelRequest(int requestId);
diff --git a/mobile/test/infrastructure/loaders/remote_image_request_test.dart b/mobile/test/infrastructure/loaders/remote_image_request_test.dart
index 66d953f842..fd1a4d6ac0 100644
--- a/mobile/test/infrastructure/loaders/remote_image_request_test.dart
+++ b/mobile/test/infrastructure/loaders/remote_image_request_test.dart
@@ -47,7 +47,7 @@ void main() {
   }
 
   test('passes the requested decode size to the platform', () async {
-    final request = RemoteImageRequest(uri: 'https://example.test/thumbnail', size: const ui.Size(320, 180));
+    final request = RemoteImageRequest(uri: 'https://example.test/thumbnail', size: const ui.Size(319.1, 179.1));
 
     await request.load((_, {getTargetSize}) => throw UnimplementedError());
 
@@ -57,14 +57,23 @@ void main() {
     expect(args[4], 180);
   });
 
+  test('leaves requests without a size unbounded', () async {
+    final request = RemoteImageRequest(uri: 'https://example.test/thumbnail');
+
+    await request.load((_, {getTargetSize}) => throw UnimplementedError());
+
+    expect(args[3], isNull);
+    expect(args[4], isNull);
+  });
+
   test('leaves encoded animation requests unbounded', () async {
     final request = RemoteImageRequest(uri: 'https://example.test/animation', size: const ui.Size(320, 180));
 
     await request.loadCodec();
 
     expect(args[2], isTrue);
-    expect(args[3], 0);
-    expect(args[4], 0);
+    expect(args[3], isNull);
+    expect(args[4], isNull);
   });
 
   test('keeps portrait cover quality in a wide tile', () async {
@@ -97,4 +106,12 @@ void main() {
 
     expect(small, isNot(large));
   });
+
+  test('shares the cache key when no decode size is set', () {
+    final first = RemoteImageProvider(url: 'https://example.test/thumbnail');
+    final second = RemoteImageProvider(url: 'https://example.test/thumbnail');
+
+    expect(first, second);
+    expect(first.hashCode, second.hashCode);
+  });
 }
diff --git a/mobile/test/presentation/widgets/images/thumbnail_resolution_test.dart b/mobile/test/presentation/widgets/images/thumbnail_resolution_test.dart
deleted file mode 100644
index 1d1f859908..0000000000
--- a/mobile/test/presentation/widgets/images/thumbnail_resolution_test.dart
+++ /dev/null
@@ -1,152 +0,0 @@
-import 'package:drift/drift.dart';
-import 'package:drift/native.dart';
-import 'package:flutter/material.dart';
-import 'package:flutter/services.dart';
-import 'package:flutter_test/flutter_test.dart';
-import 'package:hooks_riverpod/hooks_riverpod.dart';
-import 'package:immich_mobile/domain/models/asset/base_asset.model.dart';
-import 'package:immich_mobile/domain/models/config/app_config.dart';
-import 'package:immich_mobile/domain/models/store.model.dart';
-import 'package:immich_mobile/domain/models/timeline.model.dart';
-import 'package:immich_mobile/domain/services/timeline.service.dart';
-import 'package:immich_mobile/domain/services/store.service.dart';
-import 'package:immich_mobile/infrastructure/repositories/db.repository.dart';
-import 'package:immich_mobile/infrastructure/repositories/store.repository.dart';
-import 'package:immich_mobile/platform/remote_image_api.g.dart';
-import 'package:immich_mobile/presentation/widgets/images/image_provider.dart';
-import 'package:immich_mobile/presentation/widgets/images/local_image_provider.dart';
-import 'package:immich_mobile/presentation/widgets/images/remote_image_provider.dart';
-import 'package:immich_mobile/presentation/widgets/images/thumbnail.widget.dart';
-import 'package:immich_mobile/presentation/widgets/images/thumbnail_tile.widget.dart';
-import 'package:immich_mobile/presentation/widgets/timeline/constants.dart';
-import 'package:immich_mobile/presentation/widgets/timeline/fixed/segment.model.dart';
-import 'package:immich_mobile/presentation/widgets/timeline/timeline.state.dart';
-import 'package:immich_mobile/providers/infrastructure/readonly_mode.provider.dart';
-import 'package:immich_mobile/providers/infrastructure/settings.provider.dart';
-import 'package:immich_mobile/providers/infrastructure/timeline.provider.dart';
-
-import '../../../test_utils.dart';
-
-class _TimelineService implements TimelineService {
-  final BaseAsset asset;
-
-  const _TimelineService(this.asset);
-
-  @override
-  bool hasRange(int index, int count) => true;
-
-  @override
-  List<BaseAsset> getAssets(int index, int count) => [asset];
-
-  @override
-  TimelineOrigin get origin => TimelineOrigin.main;
-
-  @override
-  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
-}
-
-class _ReadOnlyModeNotifier extends ReadOnlyModeNotifier {
-  @override
-  bool build() => false;
-}
-
-void main() {
-  late Drift db;
-
-  setUpAll(() async {
-    TestWidgetsFlutterBinding.ensureInitialized();
-    db = Drift(DatabaseConnection(NativeDatabase.memory(), closeStreamsSynchronously: true));
-    await StoreService.init(storeRepository: DriftStoreRepository(db), listenUpdates: false);
-    await StoreService.I.put(StoreKey.serverEndpoint, 'https://example.test');
-  });
-
-  tearDownAll(() async {
-    await StoreService.I.dispose();
-    await db.close();
-  });
-
-  test('uses the physical tile size', () {
-    expect(getThumbnailResolution(const Size.square(214), 3), const Size.square(642));
-    expect(getThumbnailResolution(const Size.square(186.5), 3), const Size.square(560));
-    expect(getThumbnailResolution(const Size(321, 214), 3), const Size(963, 642));
-  });
-
-  test('does not cap large physical tiles', () {
-    expect(getThumbnailResolution(const Size(500, 250), 3), const Size(1500, 750));
-  });
-
-  test('marks invalid tile sizes as not ready', () {
-    expect(getThumbnailResolution(Size.zero, 3), Size.zero);
-    expect(getThumbnailResolution(const Size(double.infinity, 100), 3), Size.zero);
-  });
-
-  test('changes only timeline remote thumbnail size', () {
-    final remote = TestUtils.createRemoteAsset(id: 'remote');
-    final local = TestUtils.createLocalAsset(id: 'local');
-    final grid = Thumbnail.fromAsset(asset: remote, remoteSize: const Size.square(642));
-    final other = Thumbnail.fromAsset(asset: remote);
-    final localGrid = Thumbnail.fromAsset(asset: local, remoteSize: const Size.square(642));
-    final viewer = getFullImageProvider(remote, remoteThumbnailSize: const Size.square(642));
-
-    expect((grid.imageProvider! as RemoteImageProvider).size, const Size.square(642));
-    expect((other.imageProvider! as RemoteImageProvider).size, Size.zero);
-    expect((localGrid.imageProvider! as LocalThumbProvider).size, kThumbnailResolution);
-    expect((viewer as RemoteFullImageProvider).thumbnailSize, const Size.square(642));
-  });
-
-  testWidgets('keeps the tile while its remote decode size is unavailable', (tester) async {
-    const channel = BasicMessageChannel<Object?>(
-      'dev.flutter.pigeon.immich_mobile.RemoteImageApi.requestImage',
-      RemoteImageApi.pigeonChannelCodec,
-    );
-    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger.setMockDecodedMessageHandler(
-      channel,
-      (_) async => <Object?>[null],
-    );
-    addTearDown(
-      () =>
-          TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger.setMockDecodedMessageHandler(channel, null),
-    );
-    final asset = TestUtils.createRemoteAsset(id: 'remote');
-    final service = _TimelineService(asset);
-    const segment = FixedSegment(
-      firstIndex: 0,
-      lastIndex: 1,
-      startOffset: 0,
-      endOffset: 100,
-      firstAssetIndex: 0,
-      bucket: Bucket(assetCount: 1),
-      tileHeight: 100,
-      columnCount: 4,
-      headerExtent: 0,
-      spacing: 0,
-      header: HeaderType.none,
-    );
-
-    await tester.pumpWidget(
-      ProviderScope(
-        overrides: [
-          timelineServiceProvider.overrideWithValue(service),
-          timelineArgsProvider.overrideWithValue(const TimelineArgs(maxWidth: 100, maxHeight: 100)),
-          appConfigProvider.overrideWithValue(const AppConfig()),
-          readonlyModeProvider.overrideWith(_ReadOnlyModeNotifier.new),
-        ],
-        child: MaterialApp(
-          home: Align(
-            alignment: Alignment.topLeft,
-            child: SizedBox.square(
-              dimension: 100,
-              child: MediaQuery(
-                data: const MediaQueryData(devicePixelRatio: 0),
-                child: Builder(builder: (context) => segment.builder(context, 1)),
-              ),
-            ),
-          ),
-        ),
-      ),
-    );
-
-    expect(find.byType(ThumbnailTile), findsOneWidget);
-    expect(tester.widget<ThumbnailTile>(find.byType(ThumbnailTile)).remoteSize, null);
-  });
-}
diff --git a/mobile/test/providers/asset_viewer/asset_viewer_provider_test.dart b/mobile/test/providers/asset_viewer/asset_viewer_provider_test.dart
index 9a6f54aa5e..9d593c6933 100644
--- a/mobile/test/providers/asset_viewer/asset_viewer_provider_test.dart
+++ b/mobile/test/providers/asset_viewer/asset_viewer_provider_test.dart
@@ -109,19 +109,19 @@ void main() {
       expect(container.read(assetViewerProvider).currentAsset, updatedTwo);
     });
 
-    test('keeps the tapped tile size scoped to its asset', () {
+    test('keeps the tapped tile size while swiping', () {
       final first = RemoteAssetFactory.create();
       final second = RemoteAssetFactory.create();
       final notifier = container.read(assetViewerProvider.notifier);
 
       notifier.setAsset(first, thumbnailSize: const Size.square(642));
-      expect(container.read(assetViewerProvider).initialThumbnail, (tag: first.heroTag, size: const Size.square(642)));
+      expect(container.read(assetViewerProvider).thumbnailSize, const Size.square(642));
 
       notifier.setAsset(second);
-      expect(container.read(assetViewerProvider).initialThumbnail?.tag, first.heroTag);
+      expect(container.read(assetViewerProvider).thumbnailSize, const Size.square(642));
 
       notifier.reset();
-      expect(container.read(assetViewerProvider).initialThumbnail, isNull);
+      expect(container.read(assetViewerProvider).thumbnailSize, isNull);
     });
   });
 }