GIMP

GIMP (GNU Image Manipulation Program) is an open-source image editor written in C and GTK+. It supports a variety of raster image formats such as JPEG, TIFF, GIF, BMP, PNG, and WEBP. GIMP comes with basic image editing features such as resizing, cropping, transformation, brushes, free-form drawing, text tools, as well as image enhancement features such as filters, channels, layers, distortion correction, color correction, etc. GIMP can be extended via a community-built large collection of plugins and scripts. Written in Python, C or Script-fu, a GIMP plugin allows GIMP to interact with a third-party program or library. GIMP also supports a batch mode which allows users can perform scripted image manipulation tasks non-interactively from the command line. The latest GIMP comes with support for GPU hardware acceleration via OpenCL.