GIMP
GIMP (The GNU Image Manipulation Program) is a free image editor similar to Photoshop. It can be used for things like photo retouching, image composition and image authoring.
Features
GIMP is a fully featured image editing application, with support for many different tools.
File format support includes:
* GIMP XCF, the native format
* Autodesk flic animations (.fli)
* Scalable vector graphics for exporting paths (.svg)
* Microsoft Windows icon (.ico)
* Microsoft Uncompressed AVI Video (.avi)
* Windows bitmap (.bmp)
* Paintshop Pro image (.psp or .tub)
* Adobe PhotoShop Documents (.psd, .pdd)
* PNM image (.pnm, .ppm, .pgm, and .pbm)
* Compuserve Graphics Interchange Format (.gif)
* Joint Photographic Experts Group Images (.jpeg, .jpg, or .jpe)
* Portable Network Graphics (.png)
* Tagged Image File Format (.tiff or .tif)
* TARGA (.tga)
* X bitmap image (.xbm, .icon, or .bitmap)
* Zsoft PCX (.pcx)