You guys seem to be missing the point on what that e-mail is asking for. Fan art of heads are not applicable here. Heads that you have made (that you, by default, own the copyrights for) are the only angle you could take this in, but you'd need proof that you created the head. The people that run the site seem more than happy to take the content down upon request though, so I don't think this is going to get very far.