Pin Up Girls & Boudoir Photos. A pin-up girl, also known as a pin-up model, is a model whose mass-produced pictures see wide appeal as popular culture. Pin-ups are intended for informal display, e.g. meant to be “pinned-up” on a wall. Pin-up girls may be glamour models, fashion models, or actresses.The term pin-up may also refer to drawings, paintings, and other illustrations done in emulation of these photos. The term was first attested to in English in 1941; however, the practice is documented back at least to the 1890s. Credit: Wikipedia