Comment on ShuffleSaver

Interesting, but it currently can't show photos from a group.
Also, there's no shortcut to access the current's photo's page, only to go to the photo's author's page, which makes it hard to get information on a photo you like.

Piclens via Flickr Leech can do that quite well. Except it's more of a manual process and can't act as a screensaver. But maybe it could be scripted... :)