GIMP a free graphics manipulation package

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
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
Animation
Load and save animations in a convenient frame-as-layer format
MNG support
Frame Navigator (in GAP, the GIMP Animation Package)
Onion Skin (in GAP, the GIMP Animation Package)
Bluebox (in GAP, the GIMP Animation Package)
File Handling
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!

 

Download the latest version of gimp from here [official LInk]

 

Source:gimp.org