The best thing to use for such an illustration would be pictures of various goods and services that distinguish the poor from the rich. You could show how very different the material lives of rich and poor people are.
For example, you could show a contrast in transportation. You could have a Mercedes or other luxury car contrasted with a city bus. You could show a contrast in the kinds of schools their children go to. You could have a picture of a nice school with all sorts of playground or lab equipment and then an inner-city school with a few old books in its library. You could show differences in the types of food that are available. You could show rich people at a fancy restaurant and poor people at McDonald's. All of these would show the basic idea that you are trying to get across--the idea that rich and poor live in different worlds due to social stratification.