It is probably a good thing that the very young learn by observation and do not employ what we call logic and reason until much later in childhood. If children could verbalize their incomprehension concerning adult actions, how we would see ourselves could not be especially flattering.
This little girl was taken to the photographer's studio on two occasions about 18 months apart. I imagine the photographer (two different ones, in actual fact) telling her, "Now stand very still and look at me" and then he proceeds to stick his head under what looks like a small black blanket and fiddles with a box propped up on some sticks. This is new and strange behavior indeed, so she hardly needs to be told to look; as a child she is used to the larger people around her doing all manner of things and it is generally neither important nor useful to her thinking, nor does she expect it to have any defined purpose. On the other hand, she does take a degree of comfort in useful repetition, so when she sees something very different she will be wary and consider if she likes it or not.
The small faces that look out at us from photographs, especially photographs taken by unfamiliar people, speak volumes about the process of organizing and eventually making sense of the world they find themselves in.
The position of her foot is amusing.