Though the photo was probably taken during WWI, this print is from the 1920s.
This is a black-and-white plate from an extremely rare antique book from circa 1929. It has a blank back, meaning it was printed separately from the text for better quality and then tipped in or sewn into the book when it was bound. It would look wonderful framed.
The paper is heavy and of quality. The page measures approx. 5.6x9.1 inches, and the picture (without margins) is approx. 4x6.5 inches (10x16.5 cm).