This might help...
[?php
$sig_URL = "../../../sig.gif,jpg,swf";
$sig_dim = getimagesize($sig_URL);
$calc = $sig_URL[0] * $sig_URL[1];
if($calc >= "7201") {
echo "Your Sig Is Tooooo Big!";
}
php?]
It would need to be modified a bit to find/replace the images in the sig code, but, it's a start.
