title: Drupal - change name of uploaded images to random alphanumeric long string
body: <p>I've noticed that it is a common functionality within public sites to change the name of uploaded pictures to a long, 'random', alphanumeric string. This is good for privacy etc.</p>
  
  <p>I can't find a module within Drupal that achieves this, and was wondering if it was possible. This would need to operate before modules like ImageCache.</p>
  
  <p>???</p>