GIMP is a free and open source graphics manipulation program that is often compared to Adobe Photoshop. It has a customizable interface, supports many file formats, and runs on multiple platforms including Windows, Mac and Linux. GIMP offers extensive editing tools for images including layers, filters, and effects. While similar in functionality to Photoshop, GIMP costs $0 compared to Photoshop's retail price of $699-$999.

1. Open Source:: How Companies Can Create Profit Tom Rogers GNU Image Manipulation Program (GIMP)

10. Microsoft Windows

11. Mac OS X

12. Other Unix Type Systems

14. Layers, Layer Properties, Transparency

15. Color, Color Properties, Desaturation

16. Specialty Brushes, Selection and editing tools

20. Difference are mainly Specialized scientific formats and 3D images and animation.

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