Not sure on the webfilefetch pause/resume... not much of a way to control that right now. When there's a more full featured web client, there may be some GetRight type options, but that's better done in a multithreaded mode (Coming to ActionScript eventually).
As for the screen saver - that's what SetState should do for you, but I'll take a quick look at resetting the timer.
Pausing video - yeah, I need to offer up far more control.
Screenshot command - yes, another on my todo.
As for image/video issues, I will probably come up with a way to flush the resource caches. There's some re-achitecting to do with that stuff, though.