The poster below was produced during World War II:

A poster shows an illustration of a giant two headed beast. One head is an image of a Japanese leader and the other is an image of a German leader. The beast holds a bloody knife in his right hand and is grabbing the Statue of Liberty with his left hand. An image of the hand of an American is shown holding a wrench that reads, Production. The American hand appears to be swinging at the two headed beast. The caption reads, Stop this monster that stops at nothing. PRODUCE to the limit. This is your war.
Public Domain

Why were posters of this kind produced during the war?

to entertain people during a trying time for the nation at war
to demonstrate that an Allied victory in the war was a certainty
to unite the public in its efforts to fight against a common enemy
to show prospective troops the dangers of participating in a war