title: How to get the picture of Facebook User using Koala gem?
body: <p>I am trying to fetch the picture of a Facebook user's friends using
  their facebook ids, but using the following code returns nil instead
  of the picture url...</p>
  
  <p>The code I am using is as follows:</p>
  
  <pre><code>picture_url = @user.get_picture("1000000111")
  </code></pre>
  
  <p>where @user is the Graph API Object made using Facebook
  authentication...</p>
  
  <p>What is missing in this code?? Thanks in advance. </p>