Some viewers believe the strange detail is eerie, while others think it can be explained by early photography. Long exposure times often required people to stay perfectly still, and photographers sometimes used hidden posing stands or supports that could appear oddly in the final image.
Double exposure, slight movement, folds in clothing, and unusual shadows could also create shapes that resemble another hand. The effect may be strengthened by pareidolia, the tendency of the brain to recognize familiar shapes in unclear images.
Without the original photographic plate or notes from the photographer, the exact explanation may never be known. Still, ordinary photographic errors and visual illusions offer more likely explanations than anything supernatural.
