try changing it to:
PHP Code:
// Aceman Thumbnail of attachment on forumdisplay page
if ($forumid==102) {
$checkquery=$DB_site->query_first("SELECT postid FROM post WHERE threadid=".intval($thread['threadid'])." AND username='".addslashes($thread['postusername'])."' ORDER BY dateline ASC");
$avurl="http://www.scifi-meshes.com/forums/attachment.php?postid=" . $checkquery['postid'];
$sizes = getimagesize($avurl);
if ($sizes) {
$newwidth=$sizes[0];
$newheight=$sizes[1];
if ($sizes[0] > 100) {
$newwidth=100;
$diff=$sizes[0]-100;
$rat=100/$sizes[0];
$newheight=$sizes[1]*$rat;
}
$imagethumb="<img src=\"./attachment.php?postid=" . $checkquery['postid'] . "\" width=" . $newwidth . " height=" . $newheight . "><br>";
}
}
// END Aceman Hack