Hi,
This issue could occur if the desktop background is set as Tile for a dual monitor setup. When we select Tile for the specific desktop background, it will show separately on both the monitors. But, we will need to select span to stretch background across
both the monitors. It might also occur if the image size is small as it will repeat itself on the second display.
What is the Make and Model of the display card used on the computer?
Before we move ahead to the troubleshooting methods, I would suggest you to check if display settings changes to “Duplicate” mode from “Extended” mode. You can verify this in couple of ways:
Try to verify if you are able to drag the wallpaper to the second monitor from the first one. If you are able to, then, the display is in extended mode.
OR, you can refer to the link and follow the steps from section “Choose what's displayed on each monitor” after expanding the section “Adjust settings for multiple monitors”. Make sure that the multiple monitor setup is set as “Extend”.
For further troubleshooting, follow the methods:
Method 1:
Refer to the link to change screen resolution:
http://windows.microsoft.com/en-us/windows-8/get-best-display-monitor
If the issue still persists, proceed to the next method.
Method 2:
Refer to the link to try a different panoramic image and check if you are able to span the wallpaper:
http://windows.microsoft.com/en-in/windows/themes
For further reference, I would suggest you to update the driver for the display card be referring to the manufacturer’s website of the computer (or display card’s manufacturer). Refer to the
link to know how to update drivers on Windows 8.1. Also, refer to this
linkto know how to span wallpapers in a dual monitor setup.
Please get back to us with the status of this issue.