GIMP 2.8 is a GNU Image Manipulation Program.
GIMP 2.8 is a freely distributed program for such tasks as photo retouching, image composition and image authoring and much more.
This video gives a small impression of this great free software :
The file format support ranges from the common likes of JPEG (JFIF), GIF, PNG, TIFF to special use formats such as the multi-resolution and multi-color-depth Windows icon files. The architecture allows to extend GIMP’s format capabilities with a plug-in. You can find some rare format support in the GIMP plugin registry.
System requirements : Reasonably x86 hardware and in my experience 2 GB Ram.
Supported Platforms :
-Microsoft Windows (XP SP3, Vista, 7, 8)
-Mac OS X (10.6 and newer)