title: Posted image on a wall is too small using graph api and C#
body: <p>I am trying to post a picture on a page wall with this code:</p>
  
  <pre><code>string message = "Some message";
  string picture = "http://somesource.com/test.jpg";
  string pageToken = "page access toke";
  string pageId = "page id";
  string PostUri = "https://graph.facebook.com/{0}/feed?access_token={1}&amp;";
  
  var request = string.Format(PostUri, pageId, pageToken);
  
  
  var sb = new StringBuilder();
  sb.AppendFormat("picture={0}&amp;", picture);
  sb.AppendFormat("message={0}", message);
  
  WebClient webClient = new WebClient();
  webClient.Encoding = Encoding.UTF8;
  webClient.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
  
  var bytes = Encoding.UTF8.GetBytes(sb.ToString());
  
  webClient.UploadData(request, bytes);
  </code></pre>
  
  <p>It is works for me. But posted image using graph api has smaller size than the image posted using regular facebook web interface. What should I change in this code to display image with larger size?</p>