diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 961f064a41..e834a7305e 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -23,6 +23,8 @@
         `EditedMediaItemSequence.Builder`. If the gap is in the middle of the
         sequence, then this flag is not required.
     *   Move `Muxer` interface from `media3-transformer` to `media3-muxer`.
+    *   Make setting `MediaItem.Builder().setImageDuration(long)` mandatory to
+        import a media item as an image.
 *   Track Selection:
 *   Extractors:
     *   MP3: Use duration and data size from unseekable Xing, VBRI and similar
diff --git a/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java b/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java
index 3e8ed85ce8..21b249c6bd 100644
--- a/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java
+++ b/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java
@@ -191,6 +191,9 @@ public final class DefaultAssetLoaderFactory implements AssetLoader.Factory {
     MediaItem mediaItem = editedMediaItem.mediaItem;
     if (isImage(context, mediaItem)
         && checkNotNull(mediaItem.localConfiguration).imageDurationMs != C.TIME_UNSET) {
+      // Checks that mediaItem.localConfiguration.imageDurationMs is explicitly set.
+      // This is particularly important for motion photos, where setting imageDurationMs ensures
+      // that the motion photo is handled as an image.
       if (imageAssetLoaderFactory == null) {
         imageAssetLoaderFactory = new ImageAssetLoader.Factory(context, bitmapLoader);
       }