GIMP – GNU Image Manipulation Program
http://www.gimp.org/

GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring. It works on many operating systems, in many languages. This is the official GIMP web site. It contains information about downloading, installing, using, and enhancing it. This site also serves as a distribution point for the latest releases. This has been added to World Wide Web Reference Subject Tracer™ Information Blog.