Change NSTimer interval after a certain number of fires

Question

In the following code, the NSTimer interval is set at 1 second between each picture. My goal is to change the interval after the first two pictures, hello.png and b

Answer 1

my goal is to change the interval

You cannot change a timer in any way. To change the firing interval, invalidate and destroy the timer and make a new timer with the new interval.

To do that, you will need to have kept a reference to the timer, as a property of your view controller (something that you have fatally failed to do in your implementation - you would have had no way to stop the timer, and you would have crashed if your view controller ever went out of existence, or else your view controller would have leaked because the timer retains it).