title: Android share image URL with Facebook SharePhotoContent
body: <p>I'm trying to share a photo using Facebook's new SharePhoto &amp; SharePhotoContent classes in the new SDK. 
  I'd like to use an image URL instead of a locally stored image.</p>
  
  <p>I am able to share an image using a locally stored drawable resource:</p>
  
  <pre><code>Bitmap image = BitmapFactory.decodeResource(getResources(), R.drawable.carrots);
  
  SharePhoto photo = new SharePhoto.Builder()
                     .setImageBitmap(image)
                     .build();
  
  SharePhotoContent content = new SharePhotoContent.Builder()
                                  .addPhoto(photo)
                                  .build();
  
  shareDialog.show(content);
  </code></pre>
  
  <p>But when I try to use an image URL :</p>
  
  <pre><code>SharePhoto photo = new SharePhoto.Builder()
                         .setImageUrl(Uri.parse("http://s3-ak.buzzfed.com/static/images/public/verticals/food-title.png?v=201504021353"))
                         .build();
  </code></pre>
  
  <p>all I'm seeing is a blank post in the Facebook shareDialog.</p>
  
  <p>Has anyone else tried this and gotten it to work?</p>
  
  <p>Many thanks!</p>