From the GIMP User Manual: The GIMP is a multiplatform photo manipulation tool. GIMP is an acronym for GNU Image Manipulation Program. The GIMP is suitable for a variety of image manipulation tasks, including photo retouching, image composition, and image construction.
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.

Highlights: Free, available on Linux, similar functionality to Adobe Photoshop. Also, easily expandable with plug-ins.

Availability and Setup

The GIMP is available on the Shared Computing Cluster (SCC).

To run the GIMP, simply type gimp.

If a window does not come up for The Gimp, it is likely because you do not have X Forwarding enabled, allowing you to display graphics on your local machine from the SCC.

Using the GIMP

The GIMP is an X-Windows application with a GUI similar to that of Adobe Photoshop. It has support for reading and writing images in a large variety of formats.

Additional Help/Documentation

The GIMP User Manual is available online.

For more information on the GIMP, visit the GIMP website. An online version of the book Grokking the Gimp is another excellent resource.