Graphing

Hey all, I have been working with php for a few years but mostly simple stuff. I'm now looking at doing some graphing but have no experience with dynamic images. I have never used imagecreate but have seen one example of it and not sure if it is really what i'm after. It needs to graph changing data from a mysql db. I also understand php might not be the best option due to the server load. Just want to get peoples thoughts and suggestions. Was so looking at jquery. Looking forward your responses. Regards Ross