Giz,
Just to clarify that it should look like this then in the /admin/do_subchange.php file?
// Remove User from Group
$query = "
delete from {$config['TABLE_PREFIX']}USER_GROUPS
where USER_ID = ?
and GROUP_ID = ?
";
$dbh->do_placeholder_query($query,array($uid,$group),__LINE__,__FILE__);
// Remove Group Image from User
$group_images = "";
$query = "
UPDATE {$config['TABLE_PREFIX']}USER_PROFILE
SET USER_GROUP_IMAGES = ?
WHERE USER_ID = ?
";
$dbh->do_placeholder_query($query,array($group_images,$uid),__LINE__,__FILE__);