It's also been forked multiple times, with versions like Seashore and Glimpse attempting to improve on the original formula.Ĭoming from Photoshop, GIMP can be a tricky beast to master. Completely open source, it started out on UNIX-based systems like Linux, before being ported to Windows and macOS. For over 25 years, the GNU Image Manipulator Program (GIMP) has been one of the most popular, free Photoshop alternatives on the web.