I drank/ate a banana split blizzard from DQ within a half hour before my ultrasound and they got great pictures. They say to eat something sugary so the baby is awake and active and make sure you have a full bladder when you go but tell them cause if baby isn't corropurating they can have you go to the bathroom to get better pictures. (They had to do that for me the second time I went to get a better picture of her spine)
My baby's cord was in the way on Saturday when I went, but eventually we got some good photos lol. I just had to wait 15 minutes and tried again. I emptied my bladder and that may have helped. Also, had a naked smoothie drink. Good luck!