There was a cultural propaganda phenomena during World War II of comic book heroes, cartoons and posters with the image of Hitler getting punched. Captain America, Daredevil and the Blue Beetle all got in on the action. As well as long lost heroes like Minute-Man, Spy Smasher, Eagle and his side-kick Buddy, and good old Uncle Sam. During WWII a good number of comic book covers featured a patriotic superhero giving Adolf a good old crack on the jaw.
Weird Retro has been collecting "Punching Hitler" images for a while, a collection of which can be found on our facebook page.
While we're on with WWII propaganda, there's also the recent article on the site about Walt Disney's propaganda war effort, with some of the classic cartoons the studio produced involving the mini-moustached villain, with Walt Disney's World War II Propaganda Films.
Oh! And while digging around I came across this brilliant short film, Punching Hitler from 2004. The story of 3 drunk friends that find a time machine, and decided to go back in time and punch Hitler over and over again at different times throughout his life.
Finally... Check out the blog site Hitler Getting Punched, for more covers and artwork form the period up to now of people punching out Adolf.