feat(mobile): Precaches next image in memories (#3365)

* Precaches images in memories

* Fixes jumps and precaches images

* refactors to move precacheAsset over to ImmichImage to keep logic in same place

---------

Co-authored-by: Alex Tran <Alex.Tran@conductix.com>

mobile/lib/shared/ui/immich_image.dart

@@ -147,4 +147,46 @@ class ImmichImage extends StatelessWidget {
       },
     );
   }
+
+  /// Precaches this asset for instant load the next time it is shown
+  static Future<void> precacheAsset(
+    Asset asset,
+    BuildContext context, {
+    type = api.ThumbnailFormat.WEBP,
+  }) {
+    final authToken = 'Bearer ${Store.get(StoreKey.accessToken)}';
+
+    if (type == api.ThumbnailFormat.WEBP) {
+      final thumbnailUrl = getThumbnailUrl(asset);
+      final thumbnailCacheKey = getThumbnailCacheKey(asset);
+      final thumbnailProvider = CachedNetworkImageProvider(
+        thumbnailUrl,
+        cacheKey: thumbnailCacheKey,
+        headers: {"Authorization": authToken},
+      );
+      return precacheImage(thumbnailProvider, context);
+    }
+    // Precache the local image
+    if (!asset.isRemote &&
+        (asset.isLocal || !Store.get(StoreKey.preferRemoteImage, false))) {
+      final provider = AssetEntityImageProvider(
+        asset.local!,
+        isOriginal: false,
+        thumbnailSize: const ThumbnailSize.square(250), // like server thumbs
+      );
+      return precacheImage(provider, context);
+    } else {
+      // Precache the remote image since we are not using local images
+      final url = getThumbnailUrl(asset, type: api.ThumbnailFormat.JPEG);
+      final cacheKey =
+          getThumbnailCacheKey(asset, type: api.ThumbnailFormat.JPEG);
+      final provider = CachedNetworkImageProvider(
+        url,
+        cacheKey: cacheKey,
+        headers: {"Authorization": authToken},
+      );
+
+      return precacheImage(provider, context);
+    }
+  }
 }