The Gimp


Gimp Screenshots for Windows XP and MacOSX respectively:
   

If you've been looking for a great image editing program thats Free Software, you've found it! The GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring. It works on many operating systems, in many languages. Here is a very minimal list of its features
  • Full suite of painting tools including Brush, Pencil, Airbrush, Clone, etc.
  • Sub-pixel sampling for all paint tools for high quality anti-aliasing
  • Extremely powerful gradient editor and blend tool
  • Supports custom brushes and patterns
  • Full alpha channel support
  • Layers and channels
  • Multiple Undo/Redo (limited only by diskspace)
  • Editable text layers
  • Transformation tools including rotate, scale, shear and flip
  • Selection tools including rectangle, ellipse, free, fuzzy and intelligent
  • Advanced path tool doing bezier and polygonal selections.
  • Transformable paths, transformable selections.
  • Quickmask to paint a selection.
  • Load and save animations in a convenient frame-as-layer format
  • MNG support
  • Frame Navigator (in GAP, the GIMP Animation Package)
  • Onion Skin (in GAP, the GIMP Animation Package)
  • Bluebox (in GAP, the GIMP Animation Package)
and many others. You are free to download, customise and redistribute The Gimp. Click here to learn more about the Gimp. Scroll down the page to see the link to a windows version.