Let's remind you about the concept of pointers as we will be dealing with them in this chapter. To begin with, imagine that you have a house that you want to sell. Lacking time, you contact an agent to find interested buyers. So, you pick up your house and take it over to the agent, who will, in turn, carry the house to anybody who may want to buy it. Ludicrous, you say? Now imagine that you have a few Python functions that work with images. So, you pass high-resolution image data between your functions.
Of course, you don't carry your house around. What you do is write the address of the house down on a piece of scrap paper and hand it over to the agent. The house remains where it is, but the note containing the directions to the house is passed around. You might even write it down on several pieces of paper. Each one is small enough to fit...