GIMP

GIMP
FreeAdvanced image editing for everyone
WindowsGIMP
FreeProduce extraordinary icons, graphical design elements, and art for user interface components and mockups.
Mac
GIMP for Linux
FreeTurn to power and flexibility of transforming imagery into unique creations with sophisticated depiction tools.
LinuxGTK+ 2 Runtime Environment
FreeGet these runtime libraries for a wide range of application suites
Windows