title: Facebook Graph API returns question mark picture, post picture is visible on post page directly
body: <p>I am working on Facebook Canvas application.
  Application purpose is to access to user's accounts, collect posts and preview them posts are photo type. </p>
  
  <p>It also allows same user to see other user's posts.</p>
  
  <p>If user is looking other users' posts, preview on some of posts is question mark picture instead of image in post. If user opens post directly to post Facebook page, picture is visible.</p>
  
  <p>I am using Graph API to retrieve pictures from posts for preview.
  Current syntax is</p>
  
  <pre><code>https://graph.facebook.com/&lt;OBJECT_ID&gt;/picture?type=normal&amp;access_token=&lt;ACCESS_TOKEN&gt;
  </code></pre>
  
  <p>I tried to use page access token as well long living user access token.
  In both cases I got question mark picture.</p>
  
  <p>My questions are:</p>
  
  <ol>
  <li>Why is it not possible to see real image through application when user gave permissions to pictures?</li>
  <li>Is it possible to detect if image is question mark picture?</li>
  </ol>
  
  <p><strong>EDIT</strong>
  I use OBJECT_ID, not post ID. Preview is for photo posts. object_id in post is picture id, which can be used in pictures Graph API.</p>
  
  <p><strong>EDIT 2</strong>
  Only Graph API must be used, nothing else.</p>
  
  <p><strong>EDIT 3</strong>
  These are permissions that are requested from user: "email", "user_photos", "manage_pages", "read_stream", "read_insights", "user_hometown", "user_location", "user_birthday".</p>