Explaining pictures much like colored glass scenes in early cathedrals, where series of pictures depicting the "prophets" and "saints" in a way to explain morality - essentially these where used to empower and explain to the illiterate masses what the f*ck their religion was about to some extent.
Unless of course, you didn't want the "little people" knowing to much, perhaps then, you simply banned images of religious icons, prophets and saints and left all knowledge in the hands of the "literate" elite who ran things as they saw fit. As we saw with the Byzantine Greeks during the iconoclast and again with the Christian Persians and Arabs as Islam was formed.
Unless of course, you didn't want the "little people" knowing to much, perhaps then, you simply banned images of religious icons, prophets and saints and left all knowledge in the hands of the "literate" elite who ran things as they saw fit. As we saw with the Byzantine Greeks during the iconoclast and again with the Christian Persians and Arabs as Islam was formed.