Yes, I’ve had to do the same for coinop.org - funny that my q*bert pictures also get leeched. The other culprit (myspace is bad, yes) is ebay - people selling “emulator paks” while theiving other people’s code are also likely to thieve on the bandwidth as well. For those I usually replace them with a funny custom image involving a baby and excement and then report them to ebay for having offensive images. Then again I’m vindictive.
I have a custom image deliverer that can scale up and down images and it also checcks to make sure the referer is me. It catches 99% of the links and returns an “image missing” - figure that will confuse people and waste their time.