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 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.
GIMP is written and developed under X11 on UNIX platforms. But basically the same code also runs on MS Windows and Mac OS X.
Features and Capabilities
This is only a very quickly thrown together list of GIMP features. You can also have a look at the illustrated features overview.
Painting
Full suite of painting tools including Brush, Pencil, Airbrush, Clone, etc.
Sub-pixel sampling for all paint tools for high quality anti-aliasing
Extremely powerful gradient editor and blend tool
Supports custom brushes and patterns
System
Tile based memory management so image size is limited only by available disk space
Virtually unlimited number of images open at one time
Advanced Manipulation
Full alpha channel support
Layers and channels
Multiple Undo/Redo (limited only by diskspace)
Editable text layers
Transformation tools including rotate, scale, shear and flip
Selection tools including rectangle, rounded rectangle, ellipse, free, fuzzy
Foreground extraction tool
Advanced path tool doing bezier and polygonal selections.
Transformable paths, transformable selections.
Quickmask to paint a selection.
Extensible
A Procedural Database for calling internal GIMP functions from external programs as in Script-fu
