GIMP

GIMP (GNU Image Manipulation Program) is an open source image editor, primarily for raster images.

Native formats

 * XCF - The main GIMP image file format
 * GIMP Brush (.gbr)
 * GIMP Animated Brush (.gih)
 * GIMP Gradient (.ggr)
 * GIMP Pattern (.pat)
 * GIMP Palette (.gpl)