It is a freely distributed program for such tasks as photo retouching, image composition and image authoring.
It has many capabilities. It can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, an image format converter, etc.
GIMP is expandable and extensible. It is designed to be augmented with plug-ins and extensions to do just about anything. The advanced scripting interface allows everything from the simplest task to the most complex image manipulation procedures to be easily scripted.
Available for Debian, Fedora 9, GenToo, Slackware, openSUSE 11.0, Ubuntu, BSD, and Solaris see GIMP Home Page for details. GTK required, too.