libgd is an open source library that allows developers to dynamically generate images. It is integrated with PHP.

• Audiogalaxy.com used it to build graphs of music popularity over time. We also used it to chart internal statistics.

• Consider caching your images after generating them to reduce CPU usage.

• For generating charts of things like bandwidth or file system usage over time, consider rrdtool.
• For drawing abstract graphs and networks, consider Graphviz

• The libgd discussion archive may help you find answers to problems.