When the pictureframe object is not selected the image scales to 50% of its size with the center point in the middle if the screen. Fine when the object is selected.
Background bitmap does a similar trick when zooming.
And printing crops to 1/2 size when raster is selected.
I have looked at all the help I could find - changed Nvida settings both in Rhino and Nvida
Latest Rhino 5 Dell Precision 5510 Win7 with 4K screen (does same if set to 4k or 1080p)
Guessing it is to do with the 4k