Depends on the device you're usuing Bob. My Samsung phone uses the Power button plus one Volume button together to take a screen freeze frame.THANK YOU...and YES we are....but we (me) do limit our expertise to our fields of endeavors...specifically: thermodynamics, electrical engineering and power system design and installation, chemical plant design and start up, ASME Section VIII DIVISION 1 Boiler and Pressure Vessel Code Fabrication and testing....I use computers all the time for my work...I just do not know all the subtle intricacies of their operation....but I'll look at what you suggested...
BOB RENTON
As Cranky suggested....use google or similar to search to method for your device.