In the first one, we finally get a fat POC! The exhibit Gordon Parks: Back to Fort Scott is made up of images of people from the 1950s who went to (black segregated) grade school with the photographer, and their families and friends.
Second, going back further in time, we see some fat and not-so-thin people, both men and women, in Charles Dana Gibson’s drawings. (There are five sections, but the two linked contain the most examples.) The Gibson Girls themselves are universally slender, but many of the people surrounding them are not. (The lady near the center of the women in the background, just barely out of the shadows, looks plump. There are other, more clearly fat people in some of the other drawings in the set.)