It’s the photo that ends the movie, of Jack Nicholson in period costume composited into a photo of dozens of formally-dressed 1920s partygoers.

Matt Growcoot at PetaPixel:

After decades of mystery, the original image — sans Jack Nicholson — has finally resurfaced in a photo archive after 45 years…. no one kept a record of where, what, and who was in the original photo. Following an investigation by retired British academic Alasdair Spark and New York Times journalist Aric Toler, it has been revealed the original photo was taken by the now defunct Topical Press Agency at a St. Valentine’s Day Ball in the Royal Palace Hotel, London, on February 14, 1921.