Add photos and videos to Favorites on iCloud.com
In Photos on iCloud.com, tap the Photos tab to see your photos or videos grouped by time and location.
Tap the photos or videos you want to make a favorite, then tap the Favorites button .
The photo or video is automatically placed in the Favorites album.
If you later want to remove the photo or video from your Favorites album, tap it and tap the Favorites button again. The photo or video is automatically removed from the Favorites album, though it remains in iCloud Photos.