That looks fine to me! My kiddo had a belly like that too- in fact at 2 1/2 she still has a little bit of a pot belly. I think it's cute! But if you're too worried, just ask her doc at the next appointment.
Izzie still has a pot belly lol, and it always lookes like that in little ones i think. I know Kabe is only 4 weeks and he looks like that an awful lot as he was naked quite a lot lol. It disappears naturally, i wouldnt worry hun.