Flickle was going to be my alternative to Flickr. It's a simple full screen photo viewer.
The aim is to be able to run this rails app anywhere, link it to your Dropbox and then import any photos you drop in the Flickle app folder.
I've stopped progress on this app. If you want to use it you'll have to change the APP_KEY and APP_SECRET to that of your app.
This uses the lovely MaxImage by Aaron Vanderzwan.