I've recently run into some interesting photos of...ghosts, that have been subjected to all sorts of analysis along the years, and they still remained somehow unexplained.
The first one is the photo of the Brown Lady, and it was taken in 1936 in Raynham Hall in Norfolk, England. The ghost is supposed to belong to Dorothy Townshend, one of the former proprietaire of the house, around 1700. She was allegedly killed by her husband Charles as punishment for her infidelity.
The photo on the right was taken by the son of the woman, who was silently praying on the bench of this little church. Apparently she wasn't alone.
The photo with the girls was taken in Manilla in 2000, by their friend. There was nobody else around