I am familiar with TimThumb, which resizes images on the fly. It does this by creating and filling a cache folder on your server with these new automatically-generated images.
But I'd hear rumors that there was a way to do this without leaving as big a footprint on the server. In other words, without ending up with a cache folder full of images that just pile up over time. However, Googling the subject has yielded no results indicating that this is possible.
Am I chasing ghosts? Is a server-side cache folder really the only way to serve a dynamically-resized image in PHP to an end user?
Can't edit the OP, but here's the link to TimThumb.