Unless you stumble across it you may never know it was there, and that hidden feature of Windows 10 is too be able to easily select, and set individual monitor background images.
Have multiple monitors and would like to have the background be static and not change? With Windows 10 you can easily set the monitor background image to a picture of your choosing. It is not labeled, and it is a simple as a right click.
To add pictures to the list click Browse then locate, and select the picture you would like to add, and it will be added to the list.
Right click on the image you would like to use for the background.
Left click on Set for monitor of your choice to set the image. Repeat for each monitor.