The photo on the left is how you normally see this pose done. The photo on the right is actually the proper alignment. You will feel the difference when you support your neck and align your palate (the top of your mouth). Hold in your core and tuck your tailbone.  You must engage your muscles don’t just let go in the pose, be strong. If you want neck problems when you’re older go ahead and don’t support your neck. When your neck is happy your lower back will be happy too. You can see my lower back is arching way too much on the left and I’m losing stability in the lumbar area. Over arching your spine is never a good idea!  Only do one arm at a time if using both arms is too intense.