I just started having this issue. It began after I changed my display resolution from 3456 x 2160 to my monitor’s full resolution of 3840 x 2160. Resetting the resolution back to the original has not solved the issue. The problem only seems to happen when I use the picture frame command and insert a png file. I haven’t used many other commands yet but Picture Frame seems to be the culprit at the moment. I’m running Rhino 5 on a Lenovo W520 laptop with a Dell P2815Q monitor and an Nvidia Quadro 2000M video card. I’ve attached before and after screen shots. I also installed a registry modification that I found on this for that was to help with Rhino displaying on hi-res monitors.