However, when you use a dual monitor setup, it is quite difficult to use a single wallpaper on both of the monitors. The main problem occurs when two monitors have two different resolutions.

To set different desktop backgrounds on Windows 10, navigate to Settings > Personalization > Background, then right-click the ...

and select the Set for all desktops option to set one wallpaper on multiple displays. Change the primary monitor in Windows 10 To change the primary monitor in Windows 10, select the number ...