LibURL: more loaded questions

[David Bovill]

If you have a bunch of thumbnails that you are loading in the background and
you want to be able to make sure that a user click to see the full image is
"prioritised" is there anyway to do this except using a blocking command?
That is can you pause a(ll) load? If not is there a way of adding the
downloaded image to the cache if you have not used "load" and don't fancy
downloading it again with just in order to take advantage of subsequent
calls?