When you have dual monitors connected to your windows computer, you have two options of wallpaper. Either you can have a single wallpaper (let’s say big wallpaper spanning across your complete virtual desktop spanning both of the monitors) or you can have two wallpaper images each spanning one of your monitor. In Simple words for dual monitor windows computer, you can have seperate wallpaper images for dual monitors or one wallpaper image spanning both of your dual monitors.
The Single or Dual Wallpaper selection applies only when your monitors are connected in extended mode. In Clone Mode although you may have multiple monitors connected, but as the same desktop would be visible on all the monitors, hence this topic will be applicable only when your monitors are connected in extended mode.
In order to set a single wallpaper, you can use windows wallpaper control panel and in order to use dual wallpapers you can use Dual Monitor Software. In case you would like to have a single wallpaper image and would still like to use the Dual Monitor Software, you can switch off the functionality of the software to manage dual wallpaper images automatically by unchecking the Wallpaper Controller check box in the Monitor Background tab.