Ok, actually it seems that it does pick up the valid width and height. I just had them reversed when adding to the database

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Here's the fix. admin/doaddgraemlin.php, line 86 looks like this:
$query_vars = array($code,$smiley,$graemlin_name,1,$imagewidth,$imageheight);
That should be this:
$query_vars = array($code,$smiley,$graemlin_name,1,$imageheight,$imagewidth);