The GIMP Most of Photoshop without the price tag

GIMP is arguably the second-best example of what happens when open source software advances far enough. GIMP is an acronym for GNU Image Manipulation Program, and it has been in active development for several major PC platforms since 1995. It is currently available for Linux, Mac OS X and Windows.

GIMP is surprisingly powerful and is easily a serviceable stand-in for Photoshop for general bitmap work. It supports a huge variety of image formats in addition to its own native XCF format, supports layers, plug-ins and has a unique but rather powerful user interface which provides a very capable and stable workflow especially on multiple-desktop X11 systems.

Chief among GIMP's features however, are arbitrary layers supporting color channels, alpha channels and even alpha gradients depending on the file format. Users of Photoshop will find most of their favorite tools, just in different places.

The newest version of GIMP, version 2.4, is about to be released. It is available free under an open source-style license. There is also a recently updated manual available at the project's web site.