Actually, the most effective image protection (and by effective, I mean annoying) was on a contest site for a program called Universe Image Creator (generates star-fields, galaxies etc.). It was based on a simple right-click blocking scheme. Why didn't NoScript or View Source work? Because the entire site was served with some wtfy AJAX page-building framework, similar to Gmail (only it didn't degrade without Javascript).
Now, I don't normally feel that bad a need to copy images, but this was a [i]challenge[/i]! And I had to spend a few minutes figuring out how to solve it - thought the image URLs might be in the JS, but it was too scrambled - and then I just saved the images from the Media tab in the Page Info window. I didn't spend weeks on solving NotPron for nothing!