Simple progressive image loading

gistfile1.m

    UIView * view = [[UIView alloc] initWithFrame:CGRectMake( 0.0f, 0.0f, kAffirmationThumbnailWidth, kAffirmationThumbnailHeight )];
    view.backgroundColor = [UIColor grayColor];
    UIImageView * imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, kAffirmationThumbnailWidth, kAffirmationThumbnailHeight)];
    imageView.backgroundColor = [UIColor clearColor];
    imageView.alpha = 1.0;
    [view addSubview:imageView];
        
    // Background getting of small image and loading into memory
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void){
        NSString * imagePathSmall = [NSString stringWithFormat:@"%@_small.jpg",[[affirmation imagePath] stringByDeletingPathExtension]];
        NSData * dataSmall = [NSData dataWithContentsOfFile:imagePathSmall];
        UIImage * imageSmall = [UIImage imageWithData:dataSmall];
        [imageSmall forceLoad];
        
        // Image is loaded, set outlet on main thread
        dispatch_sync(dispatch_get_main_queue(), ^(void){
            imageView.image = imageSmall;
            
            //Load larger image
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^(void){
                NSString * imagePathLarger = [affirmation imagePath];            
                NSData * dataLarger = [NSData dataWithContentsOfFile:imagePathLarger];
                UIImage * imageLarger = [UIImage imageWithData:dataLarger];
                [imageLarger forceLoad];
             
                 // Set outlet again on main thread
                 dispatch_sync(dispatch_get_main_queue(), ^(void){
                     imageView.image = imageLarger;
                 });
            });


            // Fade Animation 
            [UIView animateWithDuration:0.2 
                                  delay:0 
                                options:(UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionCurveEaseInOut)
                             animations:^(void){
                                      imageView.alpha = 1.0; 
                                  } 
                             completion:nil];
        });
    });