I recieved 4 of those few weeks ago too.
I removed mediafire links from my signature and haven't recieved any sinse.
Unfortunately, since I want people to find my website (if they are looking for a manual), having it in my signature helps with the search engine results (doing a search for sega manual scans, or something like sega saturn manuals, you'll more than likely find a thread I posted in on any number of relevant forums to help get the word out).
I did whip up a quick script of my own to return a list of JPGs in a folder and uses a JPG component installed on my server to generate a thumbnail realtime based upon a width request and stream it to the browser, never saving it to disk (to prevent a bunch of thumbnail images from floating around).
When I hit that page, CPU peaks at 7% on the server, so while a nice idea, not realistic. My next idea was to use this same idea, but, actually have it generate the thumbnail into a local "cache" folder if one doesn't already exist. If one does exist, simply use it. That way, if I do upload a new scan, I can just empty the cache folder for that folder, and the system will regenerate the files on the next request.
It hit 8% CPU (due to some additional logic to check for a cache folder, if not there, create it, then check for a thumbnail with the requested width, if not there create it, then stream it), and subsequent runs don't even hit 1%.
So, now I just need to setup some FTP queues to run over the course of this week to move everything over, and then finish building a minimalistic UI I'm happy with (now that I've got a solution for my biggest problem, various thumbnail sizes).