title: What is the URL schema of Tumblr images?
body: <p>What is the schema of a image-file at Tumblr? (I don't mean <code>HTTP</code>)
  I've only figured out that the domain of the servers where images are stored is <code>&lt;n&gt;.media.tumblr.com</code>, where <code>n</code> is a number between 1 and 31 and the name of the image file is prefixed with "<code>tumblr_</code>.</p>
  
  <p>I'm asking because I want to find URLs that refer to the same image.</p>
  
  <p>EDIT: I'm also processing URLs from other sources, not only Tumblr.</p>