(PHP) Map generating script

[mehimz]

<?php
header('Content-Type: image/png');

        $x = 32369;
        $y = 32241;
        $z = 7;
        $image = imagecreatefrompng("./maps/".$z.".png");
        $new_width = 200;
        $new_height= 200;
        $image_new = imagecreatetruecolor($new_width, $new_height);
        imagecopyresized($image_new, $image, 0, 0, $x-100, $y-100, $new_width, $new_height,200, 200);
        imagepng($image_new);
?>

Why doesn't it work? It is suppoed to cut a part of the image... Is there something wrong with the code? I've been fighting with it on various ways still doesn't work...