Mary,
Nice drool. Is this photo already cropped from a larger image? This is a nice baby face, better than most. The lighting is nice and soft. I wish the right arm had come back into the frame.
You mentioned that you have other photo's and I suppose you posted this one because you thought it was the best. If they are all well lit then it's just a matter of finding the right composition. I rely heavily on this
cropping guide tool, but in it's absence you can devise one out of scrap paper or cardboard.
As far as which medium, I think that should be your call. I'd pick the one you can control the best, these are very subtle shifts. These babies can be a tough exercise.