I've seen how to customise the background of the login window on OS X 10.10 and 10.11 using /Library/Caches/com.apple.desktop.admin.png, but what I'd like to know is how to figure out where on the image the overlaid elements like the login fields, banner text and restart/shutdown buttons appear?
This would allow me to modify the image I want to use so that these will be more easily visible.
Thanks,
Dan Jackson (Lead ITServices Technician)
Long Road Sixth Form College
Cambridge, UK.

