title: iOS Swift Facebook SDK 4 getting user profile picture outputs "Question Mark"
body: <p>I am not an expert in programming, but I modified a code to get the user profile picture from Facebook SDK. The problem is I am getting a Question Mark in the image (<code>profilePicture.image</code>). Can anyone tell me what is going on here?</p>
  
  <p>Also, I am not sure what how to call this function to get image in viewController? At present I am directly adding profilePicture.image inside the function. </p>
  
  <pre><code>   func getProfPic(fid: String) -&gt; UIImage? {
              if (fid != "") {
                  var imgURLString = "http://graph.facebook.com/" + fid + "/picture?type=large" //type=normal
                  var imgURL = NSURL(string: imgURLString)
                  var imageData = NSData(contentsOfURL: imgURL!)
                  var image = UIImage(data: imageData!)
                  profilePicture.image = image // Returned image is Question mark 
                  return image
              }
              return nil
          }
  </code></pre>