function ApplyFilter(&$imageString, $output = null)
{
$image = imagecreatefromstring($imageString);
$imageSize = array(imagesx($image), imagesy($image));
$imageWidth = $imageSize[0];
$imageHeight = $imageSize[1];
$newImageSize = $this->GetTransformedSize($imageSize);
$newImageWidth = $newImageSize[0];
$newImageHeight = $newImageSize[1];
$result = imagecreatetruecolor($newImageWidth, $newImageHeight);
ImageUtils::EnableAntiAliasing($result);
imagecopyresampled($result, $image, 0, 0, 0, 0, $newImageWidth, $newImageHeight, $imageWidth, $imageHeight);
if ($output == null) {
return imagejpeg($result);
} else {
imagejpeg($result, $output);
}
}