gd / libgd
gd / libgd was chosen because it is an open source graphics library that appears to be widely used.
From: www.libgd.org
GD is an open source code library for the dynamic creation of images by programmers. GD creates PNG, JPEG and GIF images, among other formats. GD is commonly used to generate charts, graphics, thumbnails, and most anything else, on the fly. GD is a graphics library. It allows your code to quickly draw images complete with lines, arcs, text, multiple colors, cut and paste from other images, and flood fills. GD is not a paint program. GD does not provide for every possible desirable graphics operation. It is not necessary or desirable for GD to become a kitchen-sink graphics package, but version 2.0 does include most frequently requested features, including both truecolor and palette images, resampling (smooth resizing of truecolor images), etc.
GD has many bindings (ie: such as inclusion in PHP).
