title: How can I share an image on Facebook using FB.ui feed dialog?
body: <p>I have this script which I use for my users to share the URL of my website on Facebook. I use FB.ui's feed dialog because I need to accomplish two things:</p>
  
  <ol>
  <li>Share a message with an image</li>
  <li>Have a callback function to register when the link has been shared (this gives credits to the user).</li>
  </ol>
  
  <p>The code works. The dialog is displayed, with the correct image and text, and when is posted the callback is called. </p>
  
  <p><strong>The problem is:</strong> when I go to Facebook, the post does not have any image.</p>
  
  <p>This is the script:</p>
  
  <pre><code>var Listen = {
  
      [...]
  
      share_fb: function() {
          var self = Listen;
          var msg = 'I just voted "' + self._song.name + '" by ' + 
                  self._song.artist + ' to win a ' + self._song.prize + 
                  ' on My Website.';
          FB.ui(
              {
                  method: 'feed',
                  name: 'Come Listen to this Song',
                  link: url_base + '/listen',
                  picture: self._song.share_img,
                  source: self._song.media,
                  caption: 'mywebsite.com',
                  description: msg,
                  message: msg
              },
              function(response) {
                  if (response &amp;&amp; response.post_id) {
                      self.register_share('facebook');
                  } else {
                      console.log("Post not shared");
                  }
              }
          );
      }
  
      [...]
  };
  </code></pre>
  
  <p>I have tried with different images (<a href="https://stackoverflow.com/questions/7721687/feed-dialog-picture-not-showing-up">PNGs and JPGs</a>, all hosted on my website, <a href="https://stackoverflow.com/questions/22647805/fb-ui-feed-dialog-cannot-share-a-facebooks-picture">not on Facebook's CDN</a>). They all are displayed on the dialog but they don't show up on Facebook. </p>
  
  <p>In my latest attempt I tried using the same image (with the same URL) both on the feed dialog and on the <code>og:image</code> tag of the URL that is shared, but still nothing.</p>
  
  <p>What can be the problem?</p>