They'd either die because they couldn't afford the server bills or die because they went commercial. Some left gaping holes in forums etc when they changed.
What made it bad is that they were using the full high resolution originals, not the thumbnails, which ate bandwidth like crazy.
So I did the referrer-based leech protection and started serving those users a tiny fake error dialog image, which was much more tame than what some people used. It’s funny how quickly those people stopped embedding, even without the image being anything shocking or objectionable.