As a school website provider, it's also been a bit of a conundrum for us. It's fairly easy to do things like disabling the right-click, but that doesn't really help a lot these days as plenty of other ways to scrape an image. We just built a watermarking tool into our CMS but will continue to look out for any other methods, so I'll be monitoring this thread with interest in case anyone stumbles upon a magic formula! It's a shame a very small minority in society have caused this to be an issue.