GIMP is a versatile graphics manipulation package which is available for all major operating system free of cost. People who use Linux are very familiar of it but Windows and MAC natives are less familiar. Basically it was designed for Linux but now it is available for Windows and MAC platforms.
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.
Features and Capabilities
This is only a very quickly thrown together list of GIMP features.
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
Tile based memory management so image size is limited only by available disk space
Virtually unlimited number of images open at one time
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.
A Procedural Database for calling internal GIMP functions from external programs as in Script-fu
Advanced scripting capabilities (Scheme, Python, Perl)
Plug-ins which allow for the easy addition of new file formats and new effect filters
Over 100 plug-ins already available
Load and save animations in a convenient frame-as-layer format
Frame Navigator (in GAP, the GIMP Animation Package)
Onion Skin (in GAP, the GIMP Animation Package)
Bluebox (in GAP, the GIMP Animation Package)
File formats supported include bmp, gif, jpeg, mng, pcx, pdf, png, ps, psd, svg, tiff, tga, xpm, and many others
Load, display, convert, save to many file formats
SVG path import/export
Much, much more!