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.

GIMPShop
GIMPshop was designed to specifically ease the transition for Photoshop users. Initially, while the functionalities of GIMP and Photoshop largely overlap, window layout, options, tools, and menus have evolved independently and are quite different. This causes frustration for people who want to switch from Photoshop to GIMP or vice versa. But the latest version of GIMPshop looks and feels much more like Photoshop. Its menus, windows, tools and options are modified match the structure and conventions of Photoshop.

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