This is what I've got so far. Some of it taken from phpBB's agreement (well, open source is open, so I can use agreement text can't I?)....
* All images will be publicly visible to any visitors of the site
* Galleries must not give the impression that they are representing or otherwise making statements on behalf of YOURSITE NAME.
* You agree not to post any abusive, obscene, vulgar, slanderous, hateful, threatening, sexually-oriented images or any other material that may violate any applicable laws. Doing so may lead to you being immediately and permanently banned (and your service provider being informed).
* You must pay particular attention to copyrighted materials, including cartoons, pictures and graphics
Not sure what people think? Feel free to add or adjust.
Phil