URL is http://www.animeforum.com/banner_head/
And even though there's an index.html file in it, to prevent a directory listing from showing in a browser by simply browsing to that URL (should display the index.html file in the folder instead of the whole folder), my browser for some odd reason didn't do what it normally would, and I saw the whole directory listing! Maybe a problem in your server's configuration, I'm not sure. Well, I was just able to see the whole thing, and with that Download Helper plugin for Firefox, that lets you download all media links on a page (like pictures, etc) I just dumped the entire banners folder from your server onto my computer. That means now I have a copy of EVERY banner you've ever used for the animeforum.com website.
BWA HA HA HA HA HA! I'm now an ULTIMATE HACKER!!!!!!