The GD library is used for dynamic image creation. From PHP we use with the GD library to create GIF, PNG or JPG
images instantly from our code. This allows us to do things such as create charts on the fly, created an an anti-robot security image, create thumbnail images, or even build images from other images.
If you are unsure if you have GD library, you can run phpinfo() to check that GD Support is enabled. If you don't have it, you can download it for free.
This tutorial will cover the very basics of creating your first image. You should already have some PHP knowledge before you start.