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. You may not be able to extend a single wallpaper.
HowToGeek on MSN5mon
How to Set a Different Wallpaper on Each Monitor in Windows 10Setting different wallpapers has been a mixed experience ... right-click a background image and select "Set For Monitor 1," ...
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