GIMP 2.8.10 - Powerful, free image editing application; now a native Mac app. (Free): "The primary download link for this listing is the native build. The X11 build is still available from the secondary download link.
GIMP is a multi-platform photo manipulation tool. GIMP is an acronym for GNU Image Manipulation Program. The GIMP is suitable for a variety of image manipulation tasks, including photo retouching, image composition, and image construction.
GIMP has many capabilities. It can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, an image format converter, etc.
GIMP is expandable and extensible. It is designed to be augmented with plug-ins and extensions to do just about anything. The advanced scripting interface allows everything from the simplest task to the most complex image manipulation procedures to be easily scripted.
- Maintenance release
- Some small fixes, no new features
- OS X 10.9 or later
(Via MacUpdate - Mac OS X.)