<?php
// File and new size
$filename = PATH_WWW.'img/degrade.png';
isset($_REQUEST['q'])? $percent = $_REQUEST['q'] : $percent = 0;
$percent = $percent/100;

// Get new dimensions
list($width, $height) = getimagesize($filename);
$new_width = $width * $percent;
$new_height = $height;

$image = new Imagick($filename);
$image->cropImage($new_width, $new_height, 0, 0);

$image->setImageFormat('png');
header('Content-type: image/png');
echo $image;
?>