The GIMP is an acronym for GNU Image Manipulation Program. The GIMP is an application suitable for such tasks as retouching of photographs, composing and authoring images. Its capabilities as an image manipulation program make it a worthy competitor to other similar programs such as Adobe Photoshop or Corel PhotoPaint.
The biggest advantage of The GIMP is it's free availability (e.g. from the Internet, packaged with various Linux distrubtions, etc). Even more importantly, it's not freeware. The GIMP is an OSS (Open Source Software) program covered by the GPL license, which gives you the freedom to access and also to change the source code that makes up the program.
This is how and why GIMP is constantly being developed and improved, not only by it's core developers, but by a large amount of contributers and users.
Full suite of painting tools including brushes, a pencil, an airbrush, an ink tool, and cloning.
Tile-based memory management so image size is limited only by available disk space.
Sub-pixel sampling for all paint tools, allowing for high-quality anti-aliasing.
Full Alpha channel (transparency) support.
Layers and channels.
Advanced scripting capabilities provided by a procedural database so you can call internal GIMP functions from external scripts, such as Script-Fu, Perl-Fu (Perl scripts) and Python-Fu (Python scripts).
Multiple undo and redo, limited only by disk space.
Transformation tools including rotate, scale, shear, and flip.
File formats supported include PostScript, JPEG, GIF, PNG, XPM, TIFF, TGA, MPEG, PCX, BMP and many others.
Selection tools including rectangular, elliptical, free, fuzzy, paths, and intelligent scissors.
Plug-ins that allow for the easy addition of new functions, new file formats, and new effects filters.
The GIMP is probably most known for its use on the GNU/Linux platform, but there are many platforms that GIMP can run on. GIMP is known to work on GNU/Linux, Microsoft Windows 95, 98, NT4 and 2000, OpenBSD, NetBSD, FreeBSD, Solaris, SunOS, AIX, HP-UX, Tru64, Digital Unix, OSF/1, IRIX, OS/2 and BeOS.
Porting GIMP to other platforms is possible only due to source code availability.
The GIMP help system will provide you with the necessary information on how to use all the functions GIMP provides. It will do so in a short effective way best described as an extended quick reference. The difference between the GIMP help system and a pure quick reference is that the help system will describe how to use the functions in a productive manner as well as their functionality.
The built-in GIMP help browser has three notebook tabs: the one that help pages are displayed in, the contents tab showing a structured list of help items, and the index which shows an list of all chapters and keywords in the help system. The advantage of the built-in help browser is that you can easily navigate the help system and display the help text in the main tab. However, if you prefer, you can use Netscape Navigator (choose in the Preferences dialog) from which you can also access all parts of the help system. If you are using Microsoft Windows, your default internet browser will be used (usually either Netscape Navigator or Microsoft Internet Explorer).
Besides the description of the functionality of the functions in The GIMP, you will also find descriptions of how to organize your work with GIMP, how to configure it, various tips and tricks, a quick reference page of short cuts and modifier keys, and much more.