Found only yesterday in the attic of one of my wife's recently-deceased relatives (she was 98). They show how propaganda was used during WW1, with such cards being on general sale and the public using them to write to friends and relatives. I think you'll have to click on the images in order to make the captions readable ...

1915: A captured (fat) German.

1916: A German under fire from British sharpshooters (who never miss!) - notice how the beleaguered German is another 'fattie'

1916: Looks like this one is a dig at the Americans, who were still not involved in the war yet.

1917: Possibly nothing to do with the war at all but I just thought I'd show it anyway