Gimp – GNU Image Manipulation Program – Screenshot under Linux

GIMP in Action Under Ubuntu Linux

GIMP is an acronym for GNU Image Manipulation Program. It is a freely distributed program for such tasks as photo retouching, image composition, and image authoring.

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, or an image format converter

Examples and usage: Adobe Photoshop Alternatives For Linux Desktop