I have never seen or heard about these before, but was watching QI tonight and it came on.
Apparently, early photographic images in the late 1820s had to be exposed for hours in order to capture them on film. And when photographing squirmy children, they 'hid' the mothers so they could keep the children still.
The result, some really freaky images that look like they might have come out of a Spanish horror movie
Thats nothing, it was quite common in the Victorian era to have family photos taken with the recently deceased, especially infants as the mortality rate was very high during those days, they would stand up the corpse using a rig that was hidden from view to make them look alive.
It was called post-Mortem photography
Be warned these are some of the creepiest pics you are ever likely to see and may be upsetting for some, what has been seen cannot be unseen.