Windows/Linux/Mac: Open-source app GIMPshop is a modified version of GIMP designed to give the feel of Photoshop.
GIMPshop modifies the menu structure to closely match Photoshop's, adjusts the program's terminology to match Adobe's, and, in the Windows version, uses a plugin called 'Deweirdifier' to combine the application's numerous windows in a similar manner to the MDI system used by most Windows graphics packages.As any Photoshopper will attest, GIMP is generally not as easy to work with as Photoshop out of the box. The premise behind GIMPshop is that Photoshop users will be able to dive right into GIMP while facing only a minimal learning curve. GIMPshop is a free download for Windows, Linux, and Mac.