A picture is not (usually) worth a thousand words unless it is an illiterate society. The closer a society approaches illiteracy-the more dumbed down it gets-the more images gain an influence. So when image is everything, the bad people know it is time to make their move.
Taking over a barbaric society is much easier than controlling a learned society because the barbarians do not know how to communicate clearly. All people know intuitively the difference between right and wrong, but if nobody can articulate exactly why certain things should be done then the moochers and the pirates can have a field day.
This is how many of history's dictators and warlords came to power.
An inarticulate society can be tricked into submission using nothing but pictures, sound bites, and slogans.
Sometimes all it takes is food, and if the society is obese and addicted...fat, dumb,and happy...so much the better.