Making A Dynamic Image

Anyone have some basic guidelines on how to make a dynamic image? Say for example: A sig banner that captures content from websites or an image that captures variables that are sent to it (image.php?var=value for example)

 

This may be helpful.

http://www.phpbuilder.com/columns/rasmus19990124.php3

 

See examples of PHP GD functions:
look at this: http:// php.net/manual/en/function.imagegd.php

 

you can use gd2 for jpeg, and png generation - it's good and easy to use.
you can use imageMagic software to manipulate with graphic, make different convertions from one format to other