There were a couple of ways that photography studios could take photos of very young children & babies, depending on how old they were & how well they could sit unassisted. The kids could be held by a parent, left in a buggy, pram or stroller, propped into the corner of an over sized chair, squeezed into a small chair, or held in the lap of a parent that is covered by a blanket or piece of material.
Late 1800s-early 1900's real photo postcards made from more candid images of real people. Not models & not in a studio. The top card is French, the others are American.
Difficult to tell the boys from the girls since they all wear white gowns. Little Billy at the bottom is the only one that is labeled.