This is more to offer Help than filing a Feature Request.
I've converted the pCache class into "pCachedChart", which inherits from pChart, and is (IMHO) easier to use than pCache.
I will attach it to this request, together with 2 examples that illustrate the usage.
Simply spoken you only have to replace the constructor calls of pChart with pCachedChart, and replace the calls for Stroke() and Render() with WriteToCache() or GetFromCache() - Please see the attached files for more details.
I'd be very happy to hear from you.