gistfile1.txt

- (void)animateImageView:(UIImageView *)imageView newImage:(UIImage *)image {
    // build animation block
    CATransition *transition = [CATransition animation];
    transition.duration = 0.25f;
    transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    transition.type = kCATransitionFade;
    [imageView.layer addAnimation:transition forKey:@"image"];
    
    // set new image
    imageView.image = image;
}