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 file. This is particularly useful in World Wide Web applications, where .PNG is one 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 incorporates most of the commonly requested features for an 8-bit 2D package.