What is the correct way to Ramzi??

I've heard two opposite answers. For example, below is my ultrasound at 8 weeks. Some say (as looking at the picture) the placenta is on the right so it's most likely a boy. But others say it's wrong because you're supposed to hold the picture up to your abdomen to determine which side the placenta is on... In this case it's the left- so girl. Does anyone truly REALY know which way is correct? Thanks!