With the free ImageMagick software you can create, edit, compose or convert bitmap images.
Use ImageMagick app to easily resize, flip, replace, rotate, warp, crop, transform, adjust colors, apply various special effects or draw text, lines, polygons, ellipses and Bézier curves over an image.
ImageMagick as mentioned above is freeware provided as a binary ready to run on your system, or as source codes that you can use, copy, modify and distribute in both open and proprietary applications.
Distributed under the Apache 2.0 license.
ImageMagick uses multiple computing subsets to increase performance and can read, edit or write mega-, giga- or tera-pixel image sizes.