There is a small collection on flickr of historically interesting and humorous envelope cartoons: "A group of original and vintage WWII envelopes decorated with drawings by Corporal Weinert, an Army soldier who served during WWII. He created these works of art on envelopes he used to mail letters home to his wife." It looks like in the top one she was Miss York and in the bottom one she is Mrs. Weinert. I wonder if he wooed her with his art.
See a few more here: