GD is an open source code library for the creation of images dynamically by programmers. GD is written in C, and “wrappers” are available for Perl, PHP and other languages. GD is commonly used to generate charts, graphics, thumbnails, and most anything else, on the fly. While not restricted to use on the web, the most common applications of GD involve website development.
GD is written in C Programming Language and various binding are available for different languages like C#, clip. D, Javascript, Lua, Pearl, PHP, Pascal, Python and ruby. The library was originally developped by Thomas Boutell and is now maintained by Pierre-A. Joye under the umbrella of PHP.net.
Download: Dynamic Creation of Images