You REALLY need to do a little more research on copyright laws and the Digital Millenium Copyright Act, if you honestly think that posting a picture on this forum makes it public property.
You are taking Kingsnake's privacy policy out of context. Privacy policies relate to PRIVACY, not copyrights. That statement in the privacy policy basically warns against posting information that you don't want anyone to know, such as full names, addresses, etc. It does NOT give permission for people to steal pictures that they see posted on the forums for their own personal use. Kingsnake does not have the power to override copyright laws to that extreme. In fact, if you read the TOS you agreed to when you signed up, there are specific on Copyright infringements.
Straight from their TOS:
Posting copyrighted documents or photographs here without the owner's permission is a violation of the Digital Millenium Copyright Act (DMCA). If you have an item that was used here without your permission, you must use our Interim Designation of Agent to Receive Notification of Claimed Infringement, following the policies and procedures as required by the DMCA. Claims of infringement that are not made as outlined in the policies and procedures of the DMCA cannot be acted upon and will be disregarded. More information on the DMCA and the procedures for notification of infringement may be found at http://lcWeb.loc.gov/copyright/.
Note that NOWHERE in that copyright section of the TOS does it say that once someone posts a picture, it is public property and that anyone can use it.
To the original poster, you have the right to have that person's website shut down. Copyright infringement should not be taken lightly, as other posters seem to think. I would contact their web host, and have them take appropriate action. Most sites, such as Yahoo's Geocities, are very cooperative, and take action against copyright infringement. I have had several sites shut down for stealing my photographs and artwork from my sites.
http://lcWeb.loc.gov/copyright/