These are two "Black Americana" postcards by Detroit Publishing, dating from the early 20th century.
The first shows a young woman with the caption "Polly in the Peanut Patch"; the second is an old man with a watermelon with the caption "The Melon-Cholic days have come, the gladdest of the year".
Black Americana is a postcard collecting category, and for some people that's what they collect. In the early 20th century (and in fact much later) most postcards depicting African Americans would be considered anything from mildly to blatantly racist by today's standards. Possibly by the standards of the time too, I don't know.
Anyway these are neat cards - not only because of the subject matter, but because of the publisher. I've written about Detroit Publishing before, so I won't repeat everything in this post, you can click on "Detroit Publishing" in the labels and find another post I wrote if you want more info about them. They used a special printing (or coloring) process which I think they leased from a European company and called "Phostint", and as a result their graphics are a higher quality than most other cards printed at the time. The coloring on "Polly's" card is very nice.
These are divided back cards, so that dates them to March 1907 or later - my feeling is that they are pre-WWI.
Update: Both Sold!