Loading images async with GCD

gcd.m

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    // Do any additional setup after loading the view from its nib.
    NSString *tweetText = [_tweet valueForKey:@"text"];
    NSString *userName = [_tweet valueForKeyPath:@"user.name"];
    NSString *userDescription = [_tweet valueForKeyPath:@"user.description"];
    NSNumber *friends = [_tweet valueForKeyPath:@"user.friends_count"];
    NSNumber *followers = [_tweet valueForKeyPath:@"user.followers_count"];
    
    // Checkin'
    if ( (NSNull *)userDescription == [NSNull null] ) {
        userDescription = @"";
    }
    
    self.userNameTextLabel.text = userName;
    self.userDescriptionTextView.text = userDescription;
    self.friendsCountLabel.text = [friends stringValue];
    self.followersCountLabel.text = [followers stringValue];
    self.tweetTextView.text = tweetText;
    
    // Load images async
    dispatch_queue_t queue = dispatch_queue_create("com.app.task",NULL);
    dispatch_queue_t main = dispatch_get_main_queue();
    
    dispatch_async(queue, ^{
        NSString *urlString = [[_tweet valueForKeyPath:@"user.profile_image_url"] stringByReplacingOccurrencesOfString:@"_normal" withString:@"_bigger"];
        NSURL *url = [NSURL URLWithString:urlString];
        UIImage *profile = [UIImage imageWithData:[NSData dataWithContentsOfURL:url]];
        
        dispatch_async(main, ^{
            self.profileImageView.image = profile;
            [self.profileImageLoading stopAnimating];
        });
    });

    dispatch_async(queue, ^{
        NSString *urlString = [_tweet valueForKeyPath:@"user.profile_background_image_url"];
        NSURL *url = [NSURL URLWithString:urlString];
        UIImage *backgroundImage = [UIImage imageWithData:[NSData dataWithContentsOfURL:url]];
        
        dispatch_async(main, ^{
            self.background.image = backgroundImage;
        });
    });
    
    dispatch_release(queue);
}