Feedify makes Atom feeds out of your friends' Flickr and Instagram photo feeds, and other things that don't already provide them, because I like subscribing to things in a feed reader rather than having to check everything every day.
As with most stuff I make it's fragile and will probably break. And you have to be quite nerdy to understand why you'd even care. Nevertheless, I like it.
Feedify is live at http://feedify.movieos.org/