I don't think this is a p.m. photo.
The pose doesn't look right.
Usually children are posed lying down either in a crib or mother's arms.
You do see some where children are posed to appear alive but I don't think this is one.
There was a practice I believe of some photographers giving problematic children
a drop of Laudanum to quiet them down but I don't know how common that was.
Skirts usually didn't come with pockets so where does one put one's hanky?