<?php
function renderImage($imageResource, $imageType)
{
  switch ($imageType) {
  case 'jpg':
  case 'jpeg':
    header('Content-type: image/jpeg');
    imagejpeg($imageResource);
    break;
  case 'png':
    header('Content-type: image/png');
    imagepng($imageResource);
    break;
  default:
    throw new DomainException('Unknown image type: ' . $imageType);
    break;
  }
  imagedestroy($imageResource);
}
?>