function comment_on(image_id, image_key) {
    if ($("#commentform_"+image_id).length) return;
    $("#comment_link_"+image_id).after('<form method="post" action="/comment" id="commentform_'+image_id+'"><table><tr><td>Your name:</td><td><input type="text" name="name" size="30"></input></td></tr>'+
                           '<tr><td>E-mail:</td><td><input name="email" type="text" size="30"></input></td></tr>'+
                           '<tr><td></td><td><small>(Your email will NOT be published)</small></td></tr>'+
                           '<tr><td>Comment:</td><td><textarea name="body" rows="5" cols="30"></textarea></td></tr>'+
                           '<tr><td></td><td><input type="submit" value="Post comment!"</td></tr>'+
                           '<input type="hidden" name="image_id" value="'+image_key+'"/>'+
                           '<input type="hidden" name="return_url" value="'+(location.href)+'"/>'+
                           '</form>');
}