Actually, I KNOW you can tell at 12 weeks if the baby is in the right position and the tech is very skilled. We found out at 12+6 with my older boy. We have the potty shot (from underneath) and it is pretty obvious he is a boy. The tech told me things would be more "tucked" if it was a girl. She could not give me any 100% or anything like that (she said she was going with 80% to be "safe"), but the shot is nothing but boy and he showed us that every single sono afterwards. And still loves to show it off at age 2! The tech had been scanning for over 20 years and said she often can 'tell' even if the legs are crossed at 20 weeks. So I totally trusted her. She guessed boy for our second off of the 12 week sonogram, which we confirmed at 16 weeks. But we did not get a good potty shot with him.
That said, I don't think this shot is actually good for determining gender. With Liam, his potty shot was even tiny. The parts you think are his boy parts in that picture are probably a foot, a cord, a tailbone, or some other part. His genitals would not be that large in comparison to his body (check out how the foot is about the same size as the area you are talking about). Chances are something is blocking the actual genitals. On the 12 week one we had, Liam's were about the size of your 1-year-old's pinkie fingernail. But they did have form, which was what she went off of
Although...I could always be wrong. I am not at all a sono tech, nor do I play one on Tv