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.
gd is not a paint program. If you are looking for a paint program, you are
looking in the wrong place. If you are not a programmer, you are looking
in the wrong place.
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 1.7.3 incorporates most of the commonly requested
features for an 8-bit 2D package. Support for truecolor images, including
truecolor JPEG and PNG, is planned for version 2.0.