We can directly change the registry setting where the wallpaper image location is stored (in Win10 is HKEY_CURRENT_USER\Control Panel\Desktop).

 

The above can be automated using the “reg add” command through the “Run DOS Command” Action.


reg add "HKEY_CURRENT_USER\Control Panel\Desktop" /v wallpaper /t REG_SZ /d C:\Users\your_user_name\Desktop\hi.jpg /f


*Adjust the image path accordingly.