$src = ImageCreateFromJPEG('test.jpg');
$width = ImageSx($src);
$height = ImageSy($src);
$x = $width/2; $y = $height/2;
$image = ImageCreateTrueColor($x,$y);
ImageCopyResampled($image,$src,0,0,0,0,$x,$y,$width,$height);
header('Content-Type: image/png');
ImagePNG($image);
?>