Movies that we see are separate pictures but we see a moving picture. How? 

The impression of an image does not vanish immediately from the retina. It persists there for about 1/16^th of the second. So, it image flash on the eye at a rate faster than 16 per second, then the eye perceives a moving picture of the objects. The movies that we see are actually separate pictures. They are made to move across the eye usually at the rate of 24 per second (faster than 16 per second).