"I originally found this image in the form of a celluloid negative, hidden among countless others; they were all packed away in dusty boxes in the attic of my family home.
The woman on the couch is my Aunt Theo, and I believe the photo was taken in the mid 1930s at 20 South Montgomery Ave., Bayshore, Long Island, NY." - Jess
During the early part of the 20th century (and late 19th century), it was common for photographer to lengthen film exposures to create various effects. One of the more popular tricks were to allow people to walk in and out of frame during a long exposure of the film. This would create ghosts that could be used for novelty or to convey the idea of family members with loved ones.
During World War I, especially, double-exposures were used by photographers to place images of deceased loved ones, often soldiers, in the atmosphere of the photographic frame around the family. It was a unique way to honor the dead by showing them still with their families while in "spirit form."