That's strange -- I've been familiar with the Nesbitt image for years, and never throught it was anything but a tacky illustration of a notorous woman. Printed "backwards" as your first illustration, however, I find it extremely sensual, almost erotic.
Much later, Dorothea Lange made an image similar to Red Man, which I've always admired, but the Kaesebier is even finer.
Thank you for presenting these. I'll have to look up Gertrude in more detail.