The GDmodule is an interface to the GD library written by Thomas Boutell.
'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, and write out the result as a PNG or
JPEG file. This is particularly useful in World Wide Web applications,
where PNG and JPEG are two of the formats accepted for inline images
by most browsers.'
