title: How can I make a greyscale copy of a Surface in pygame?
body: <p>In pygame, I have a surface:</p>
  
  <pre><code>im = pygame.image.load('foo.png').convert_alpha()
  im = pygame.transform.scale(im, (64, 64))
  </code></pre>
  
  <p>How can I get a grayscale copy of the image, or convert the image data to grayscale? I have numpy.</p>