getting the head of a player's skin

how do i get the head of a player's skin and save it as png?
i tried using gd:

PHP:

$skin_data = $sender->getSkin()->getSkinData();
        $size = 48;

        $im = imagecreatefromstring($skin_data);
        $av = imagecreatetruecolor($size, $size);

        imagecopyresized($av, $im, 0, 0, 8, 8, $size, $size, 8, 8);
        imagecolortransparent($im, imagecolorat($im, 63, 0));

        $png = imagepng($av);

but returns

Code:

[19:45:12] [Server thread/CRITICAL]: ErrorException: "imagecreatefromstring(): gd warning: one parameter to a memory allocation multiplication is negative or zero, failing operation gracefully" (EXCEPTION)

 

Hi, I have exactly the same error, did you solve it ?

 

no i didnt