Le Sourire 03 05 1928 - Drawing. Public domain image.

The term pin-up may refer to drawings, paintings, and other illustrations as well as photographs. The term was first attested to in English in 1941. Pin-up images could be cut out of magazines or newspapers, or on a postcard or lithograph. Such pictures often appear on walls, desks, or calendars. Posters of pin-ups were mass-produced and became popular from the mid 20th century. A pin-up model (known as a pin-up girl for women and less commonly as a pin-up man for men) is a model whose mass photographs are widely popular in popular culture. Pin-ups are designed for informal display, in other words, they are designed to be "attached" to the wall. Pin-up style models can be glamorous models, mannequins, or actors. These photos are also sometimes referred to as "cheesecake photos". "Cheesecake" was an American slang word that was considered a publicly acceptable term for a semi-naked woman because pin-up was considered taboo in the early twentieth century