The Python Flickr API kit is a feature-rich Python interface to the Flickr API. It comes with a caching framework and remembers the user's authentication credentials automatically. It supports a variety of communication protocols, and offers different XML parsers to suit different platforms and preferences.
The popular picture-sharing empire behind I Can Has Cheezburger lets you view, caption and share funny images. You can do this via its sites and, the now, thanks to their API, you can do it via code (technical details at our Cheezburger API profile).