Found this last weekend. This card of a lightly attired showgirl was produced in the 1920s by a Chicago company called Exhibit Supply.
Exhibit Supply made vending machines that, for a penny or two, dispensed photocards. The company produced cards of all sorts of subjects: baseball players, boxers, cowboy heroes, movie stars, cartoon characters, sideshow freaks, wrestlers, jokes and gags, fortunes, and pin-up girls.
The vending machines—especially the ones selling girlie pictures—were often located in theaters, pool halls, arcades, bars, military PXs, and other places young men gathered.
Exhibit Supply maintained a steady business and produced thousands of cards until the late 1960s when it finally succumbed to changing market conditions.