Drag your cursor over a gallery to "flip" through its photos, and click anyone to view. Once you've entered a gallery (Apple is still rather reflection crazy), you've got several options. Choose a grid, carousel or mosaic layout (the carousel is impressive), or simply start a slideshow. You may also change the background's color and resize any photo. Finally, you can subscribe to an album's RSS feed, send to a friend or add photos (if you've got permission to do so).
Play any movie with a click, and select desired size. From there, you can easily send it to a friend of download for safe keeping.