GD is an open source code library for the dynamic creation of images
by programmers. GD is written in C, and wrappers are available for
Perl, PHP and other languages. GD creates PNG, JPEG, GIF, WebP, XPM,
BMP images, among other formats. 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.