<?php
header ("Content-type: image/png");

$img = $_GET['img'];
$percent = $_GET['percent'];
$constrain = $_GET['constrain'];
$w = $_GET['w'];
$h = $_GET['h'];

// get image size of img
$x = @getimagesize($img);
// image width
$sw = $x[0];
// image height
$sh = $x[1];

if ($percent > 0) {
	$percent = $percent * 0.01;
	$w = $sw * $percent;
	$h = $sh * $percent;
} else {
	if (isset ($w) AND !isset ($h)) {
		$h = (100 / ($sw / $w)) * .01;
		$h = @round ($sh * $h);
	} elseif (isset ($h) AND !isset ($w)) {
		$w = (100 / ($sh / $h)) * .01;
		$w = @round ($sw * $w);
	} elseif (isset ($h) AND isset ($w) AND isset ($constrain)) {
		$hx = (100 / ($sw / $w)) * .01;
		$hx = @round ($sh * $hx);

		$wx = (100 / ($sh / $h)) * .01;
		$wx = @round ($sw * $wx);

		if ($hx < $h) {
			$h = (100 / ($sw / $w)) * .01;
			$h = @round ($sh * $h);
		} else {
			$w = (100 / ($sh / $h)) * .01;
			$w = @round ($sw * $w);
		}
	}
}
$im = @ImageCreateFromPNG ($img) or // or PNG Image
?>