/a/ in need of some dire help

Dear /prog/enitors.

We need your help.

Some idiot script kiddie has written a script that spams /a/ with the same image rotated by 90 degrees.  at the moment it is fucking the mods over because the content is changing therefore they cant ban by ip.

What im asking is for you guys to come up with a way to combat this spam.  Cheers

I don't think image recognition is an option either because of cpu-usage (have to compare the same image against many previous images). Also once you get the system in place, the spammer can just add a new twist to his software which will bypass the spam-protection. There are hundreds of filters at his disposal for making his every image a bit different.

I've made a few webabusers my own (nothing related to spam), and the most interesting part about is trying to bypass someone elses bot-detection. Honestly, the only way you can really stop him is to use a good CAPTCHA. And those really aren't an option.