these to secure the frames from swinging back and forth while on the nail and to secure them and keep them level. They are great and I highly recommend doing something similar otherwise your frames will move and not stay straight
"We built the low wall against the back wall of the tub as a place to store shampoo, soap, etc. without resorting to one of those over the shower caddies. Best of all, everything is within an easy arm’s reach whether you’re taking a shower or bath." good idea.