Graph Image Cache

[syshackmin]

This would kinda go along with the feature to generate static pngs for the graphs. How about also having the ability to just cache things that have been recently viewed... I know on my machine if I set it to staticly generate all the graphs at any interval it would take a considerable amount of time and probably cause the data collection to fall behind. A graph cache would cache graphs that have just been viewed. That way when another tree is expanded the graphs that are already displayed don't have to be generated again. I don't have a very powerful machine to run this on so having to generate each graph over and over just to navigate around takes a considerable amount of time.