You will need to research "PROPAGANDA" for an answer to this. You might start with the book by that name, written by Edward Bernays. The book was written in 1928, but is widely available today reprinted for about ten dollars. Bernays was the father of spin. The Nazi propagandist, Goebels had a copy of that book on his desk! They learned it from our (USA) advertisers. The Nazi's gave propaganda a bad name, so, modern propagandists changed the name to "PUBLIC RELATIONS." The U.S. military uses propaganda from a unit called "PSYOPS" That's PSYchological OPerations. They are based here in the state of Missouri somewhere. I think if you research those things you will find some answers.
Here is my understanding of ART IN REVOLUTION: It is used to form public opinion. Personal beliefs are shaped by art (and other forms of communication). If you think you came to a conclusion ON YOUR OWN... then you keep it as a TRUTH.
A poster of a dictator shows him strong and powerfull and intelligent looking. You sub-consciously believe those things because of the SUBLIMINAL clues in the picture. Propaganda that preaches LIES is not very effective because we see the falseness of it. Propaganda in ART is more subtle. The lie is more difficult to see... so the viewer thinks he has come to his own conclusions and believes what the art portrays.
You can see these things in the Hitler poster here. Why is Hitlers arm raised high on the pole. Why is Hitlers other hand in a fist? Why are the masses of people saluting him in the background. Why is the eagle symbol in the sky/background? Why is his face so determined looking? All of these are subliminal clues in the propaganda poster.