I'm with Jim!
Have seen many photos described as post mortem, many are, others are less certain & some are very doubtful...I don't think this is a post mortem image at all.
I'd say this little poppet's appearance is due to any one of, or any combination of: pale eye colour, visual impairment, other physical/intellectual disability, propensity to bolt when anxious, simple non-compliance

(It would be interesting to discover more about this child's fate!)
In this period, such a special event as having a photo taken, would, I think, see the parents wanting to present their children to best advantage, as they perceived it. Crouching behind a curtain to covertly direct/encourage/support/manage is quite common with unsettled littlies.
There is such a lovely tenderness in the older child's supportive pose, isn't there?