ios - use time with switch statment or if statment?

is it possible to use if statment or switch statment with time? to be more clear, I want a photo to change every one day, i want photo1 now, photo2 after 24hours, and so on. or is it more common to use date? if 01/22/2015 photo1, 01/23/2015 photo2, and so on.

How should I solve this? thanks!