Propaganda is “information, especially of a biased or misleading nature, used to promote or publicize a particular political cause or point of view.” So you can say just about everything you see during the day is propaganda. The use of propaganda during wartime is almost as old as war itself and certainly has had its place in American Military History.
The examples that you see in the picture are from the Korean conflict. Pamphlets like these were disseminated to the general population to convince them that the UN/South Korean troops were the good guys. The goal was to either get people to fight, flee, or at least not support the enemy. There is an ongoing debate as to how effective it is or was during this conflict. Other times the effective use of propaganda has proven very valuable.
Before and during the American Revolution the use of propaganda was vital to sway people to the side of the rebels. Paul Revere’s engraving of the Boston Massacre that took some liberties with events. The stories that surrounded young Jane McCrea led to the British defeat at Saratoga. Propaganda proved an invaluable tool in gaining the support needed to win the American Revolution.
Several times it was not just used to gain support for a war, but to actually get one started!
During the lead up to the Mexican War is an example. The administration was able to convince the people that Mexican soldiers had attacked American soldiers on American soil. (A dubious and purposeful claim that a young Abraham Lincoln took exception to.)
Don’t forget using the sinking of the USS Maine to throw us into war against Spain. There many more examples in our history. Now expand that to the rest of the world. It seems that propaganda is just as important as guns and money to starting, fighting and winning a war.