jpg resize code not working for png

[jsalita]

I have code that I've been using to successfully resize jpgs. I figured that all I needed to do to make this work for pngs would be to replace all instances of jpeg/jpg with png and that it would work just fine. However, the resized image does not show up. What am I doing wrong?

 

<?php
$filename = $_GET['file'];

$width = $_GET['width'];
$height = $_GET['height'];

header('Content-type: image/png');

list($width_orig, $height_orig) = getimagesize($filename);

$ratio_orig = $width_orig/$height_orig;

if ($width/$height > $ratio_orig) {
   $width = $height*$ratio_orig;
} else {
   $height = $width/$ratio_orig;
}

$image = imagecreatefrompng($filename);

$image_p = imagecreatetruecolor($width, $height);
$ret = imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig);

imagepng($image_p, null, 100);
?> 

[hansford]

the args are not the same for jpeg.

http://us3.php.net/imagepng