The easiest way to show animated image/gif on a UIImageView in iOS would be to give it the collection of images to animate, and call startAnimation
UIImageView* imgView = [[UIImageView alloc] init];
imgView.animationImages = [NSArray arrayWithObjects:
[UIImage imageNamed:@"imgAtPosition1.gif"],
[UIImage imageNamed:@"imgAtPosition2.gif"],
[UIImage imageNamed:@"imgAtPosition3.gif"],
[UIImage imageNamed:@"imgAtPosition4.gif"],
.
.
., nil];
imgView.animationDuration = 0.4f;
imgView.animationRepeatCount = 100;
[imgView startAnimating];