title: Why isn't get_serving_url() cropping working correctly?
body: <p>According to <a href="https://developers.google.com/appengine/docs/python/images/functions#Image_get_serving_url" rel="nofollow">the App Engine docs</a> there's a method <code>get_serving_url</code> which gives a URL to an image in the blobstore that can then be resized an cropped. So I can take a URL like:</p>
  
  <p><a href="http://lh4.ggpht.com/TgjDT-cPRr6bjrpSVQeILk93o4Ouzjo1ygMB6KpmnCHhyH5vJKKRrqxCD2bC3T09CRIP6h5QFsV_l0hnhio5bN7z" rel="nofollow">http://lh4.ggpht.com/TgjDT-cPRr6bjrpSVQeILk93o4Ouzjo1ygMB6KpmnCHhyH5vJKKRrqxCD2bC3T09CRIP6h5QFsV_l0hnhio5bN7z</a></p>
  
  <p>add <code>=w300-c</code>:</p>
  
  <p><a href="http://lh4.ggpht.com/TgjDT-cPRr6bjrpSVQeILk93o4Ouzjo1ygMB6KpmnCHhyH5vJKKRrqxCD2bC3T09CRIP6h5QFsV_l0hnhio5bN7z=w300-c" rel="nofollow">http://lh4.ggpht.com/TgjDT-cPRr6bjrpSVQeILk93o4Ouzjo1ygMB6KpmnCHhyH5vJKKRrqxCD2bC3T09CRIP6h5QFsV_l0hnhio5bN7z=w300-c</a></p>
  
  <p>and it should turn into a 300x300 square image.</p>
  
  <p>Except, at the time of writing this post, the image that is returned by the 2nd of the above URLs is horribly malformed.</p>
  
  <p>Is this a bug? Or am I doing something wrong?</p>