title: Calls to NSURLConnectionDataDelegate methods to download images only works occasionally
body: <p>I currently have two <code>UIImageView</code>s in my storyboard, one of which downloads my own Facebook profile picture, and the other a friend's profile picture.</p>
  
  <p><img src="https://i.stack.imgur.com/gt9FB.png" alt="Storyboard layout"></p>
  
  <p>However, my issue is that <strong>only 60% of the time this works as expected</strong>, while the other 40% of the times my own profile picture appears where my friend's picture should show in the bottom, while the top box remains empty.  I am unsure whether this is the result of how I call the <code>NSURLConnectionDataDelegate</code> methods as it downloads or completes view, or the nature of my requests called to Facebook.</p>
  
  <p>I've pasted the condensed version of my two requests to Facebook in <code>viewDidLoad</code>, one which gets my own profile pic, and the other to get my friend's pic:</p>
  
  <pre><code>// ----- Gets my own profile picture, using requestForMe -----
  FBRequest *request = [FBRequest requestForMe];
  [request startWithCompletionHandler:^(FBRequestConnection *connection, id result, NSError *error) {
      //handle response
      if(!error){
          //Some methods not included for breveity, includes facebookID used below
          NSURL *pictureURL = [NSURL URLWithString:[NSString stringWithFormat:@"https://graph.facebook.com/%@/picture?type=large&amp;return_ssl_resources=1", facebookID]];
          self.imageData = [[NSMutableData alloc] init];
          switcher = 1;
          NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:pictureURL cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:2.0f];
          NSURLConnection *urlConnection = [[NSURLConnection alloc] initWithRequest:urlRequest delegate:self];
          if (!urlConnection){
              NSLog(@"Failed to download picture");
          }
      }
  }];
  // ----- Gets a profile picture of my friend, using requestForMyFriends -----
  FBRequest *requestForFriends = [FBRequest requestForMyFriends]; 
  [requestForFriends startWithCompletionHandler:^(FBRequestConnection *connection, id result, NSError *error) {
      if(!error){
          //Other methods not included, including facebookFriendID
          NSURL *friendPictureURL = [NSURL URLWithString:[NSString stringWithFormat:@"https://graph.facebook.com/%@/picture?type=large&amp;return_ssl_resources=1", facebookFriendID]];
          self.supportImageData = [[NSMutableData alloc] init];
          switcher = 2;
          NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:friendPictureURL cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:2.0f];
          NSURLConnection *urlConnection = [[NSURLConnection alloc] initWithRequest:urlRequest delegate:self];
          if (!urlConnection){
              NSLog(@"Failed to download picture");
          }
      }
  }];
  </code></pre>
  
  <p>Both requests make calls to the <code>NSURLConnectionDataDelegate</code> methods, and I use the <code>switcher</code> to decide when to load which picture:</p>
  
  <pre><code>- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
      // As chuncks of the image are received, we build our data file
  
      if (switcher == 1) [self.imageData appendData:data];
      if (switcher == 2)[self.supportImageData appendData:data];
  }
  
  - (void)connectionDidFinishLoading:(NSURLConnection *)connection
  {
  
      //When the entire image is finished downloading
      if (switcher == 1) {
          UIImage *image = [UIImage imageWithData:self.imageData]; //puts the completed picture into the UI
          self.titleImageView.image = image;
          [self.titleImageView setClipsToBounds:YES];
      }
  
      if (switcher == 2) {
          UIImage *supportImage = [UIImage imageWithData:self.supportImageData];
          self.supportImageView.image = supportImage;
          [self.titleImageView setClipsToBounds:YES];
      }
  }
  </code></pre>