How to Shrink Image to Fit on Screen (FX5200)

I feel really dumb asking this, but I can't figure out how to reduce
the size of my window to fit on the screen. The top (or the bottom)
doesn't show in the window. I don't have access to the menu bars and
the bottom task bar at the same time.

I can see how to change the resolution, and how to reposition the
image, but not how to shrink the window to fit on my monitor.

I'm using Nvidia driver 71.89.

Thank you for your time and help;
Frank