This is all I have in there:
/threads/images/captcha/index.html
/threads/images/captcha/backgrounds/background1.jpg
/threads/images/captcha/backgrounds/background2.jpg
/threads/images/captcha/backgrounds/index.html
/threads/images/captcha/fonts/bullpen_.ttf
/threads/images/captcha/fonts/eflb.ttf
/threads/images/captcha/fonts/index.html
When I look in
/threads/cache/ there are a bunch of 10-byte gifs with names like 2ad1673ef91ae1237dce569622afff72.gif -- but I cannot open them (they're apparently corrupt). I can delete them, but they just come back when someone goes to the registration page.