flickr-tools is a collection of python scripts to do stuff with images, with a focus on the web image service http://www.Flickr.com. These tools are free software and licensed under the terms of the GPL.
Tarballs are available in the downloads directory: http://johnleach.co.uk/downloads/flickrtools
Python interpreter ( probably version 2.2 or above ) - http://www.python.org
Python Imaging Library - http://www.pythonware.com/products/pil/