title: Storing kABPersonImageFormatThumbnail for an address book contact
body: <p>I'm trying to store the thumbnail for a contact in the address book.</p>
  
  <p>The following allows me to retrieve both the thumbnail and the full image:</p>
  
  <pre><code>ABPersonCopyImageDataWithFormat(contactRef, kABPersonImageFormatOriginalSize);
  (NSData*)ABPersonCopyImageDataWithFormat(contactRef, kABPersonImageFormatThumbnail);
  </code></pre>
  
  <p>And this allows me to store the full image:</p>
  
  <pre><code>ABPersonSetImageData(contactRef, (__bridge CFDataRef)UIImagePNGRepresentation(selectedImage), nil);
  </code></pre>
  
  <p>But I cannot figure out how to store the thumbnail. There doesn't seem to be a method that takes <code>kABPersonImageFormatThumbnail</code> as a parameter to store the image. Is this possible?</p>