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.
If you are building an image sharing service or a social network mashup, it's likely that you will want to incorporate face-tagging in your images. Maybe you'd like to go a step further and automatically detect faces in an image, similar to Apple's iPhoto. A Romanian developer has developed an API to help detect faces in images and return the box coordinates so that you can build any kind of app you want.