By the way, there's a new issue I just discovered. XMonitor won't work with a Linux computer, at the moment. Or, it's not supposed to. I haven't gotten any specific complaints about that yet, but it might be the undiscussed reason for some of the problems people have had.
I'm using a simple, convenient screenshot function that, I just learned, only works on Windows systems.
What I've decided to do is keep XMonitor mostly as-is, for non-HD, Windows users (I'm going to add some error handling to keep it from flashing the splash screen too often, though). Then I'm also going to develop an "XMonitor HD" variant which will capture higher-resolution screen shots (whatever res your PC's display is set to) and send THEM, instead of the 72 dpi images that my current function creates.
And, totally unrelated to HD, the type of screenshot utility I'll use there SHOULD work for Linux. It'll take me a while to be sure, because I don't have a Linux box to test on, but from what I've read that should be pretty easy to get working. So Linux users OR HD users can make use of "XMonitor HD" once it's out.
Of course, higher-res screenshots will take longer to transfer, so it will be a slower refresh rate and longer lag than the normal script, but at much higher image quality. Maybe it'll be worth it. We'll see.