$mysqli = new MySQLInterface(); // This is just a wrapper I wrote for the normal mysqli
$query = "SELECT image_data ,image_size FROM image WHERE image_id = '".$id."'";
$result = $mysqli->Query($query);
$imagedata = $result['image_data']; // Works with my wrapper
$image = imagecreatefromstring($imagedata);
$image_p = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
header('Content-Type: image/png');
imagepng($image_p);