Also, Just reminder. Try and keep your elbows in line. Try to bring them back a little bit. That way, they should bend and not be too stiff. In the pictures, they aren't that stiff. Just a reminder.
Also, I always got taught to hold your not too loose, as it's hard to control. I also got taught that when you hold then reins, hold your hands up, so your thumbs are in the air and not pointing outwards. Because, imagine that you have a cup of tea in your hands, keep your hands up so you don't spill it on your horse and burn him.
But, you can really hold the reins anyway you want.
Hoped I helped,