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.

After choosing the Advanced span mode, you need to select the wallpaper source folder ... the placement from here if the monitors are not placed correctly. Two more options for Superpaper are ...

If you want to hook up your laptop or computer to a dual 4K monitor setup, then you may need a Thunderbolt dock. Here are ...