ImageMagick is a software suite to create, edit, and compose bitmap images. It can read, convert and write images in a variety of formats (over 100) including DPX, EXR, GIF, JPEG, JPEG-2000, PDF, PhotoCD, PNG, Postscript, SVG, and TIFF. Use ImageMagick to translate, flip, mirror, rotate, scale, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and Bézier curves.
Home Page: http://www.imagemagick.org/
Language: C with API's provided for C++ and Perl
Platform: Windows, Linux, OSX
License: Custom open source license that requires attribution. Free for commercial use. GPL compatible.