GIMP can be simply installed with the homebrew package installer. The latest GIMP is better than ever Step 2 - Install GIMP on macOS. This takes one annoying step out of the installation process.
If you are Tiger or Leopard user, you can install GIMP 2.6.If you are using Snow Leopard and above can use the latest version of GIMP (right now, that's GIMP 2.8.4) Mac users will be happy to know that GIMP 2.8.2 is the first version of the program to run natively in OS X, without requiring the installation of X11. In order to install GIMP, you will need Mac OS X. Home Gimp on mac How to Install GIMP for Mac - Expert Hoo
