I have not tried this but, you should be able to include the wallpapers without ticking the "Include the user data files", by adding the wallpapers to You just need to open the folder as administrator and paste them in, and then set their permissions to match the existing images in the folder.
Code:
/usr/share/backgrounds/xfce/
“I have not failed. I’ve just found 10,000 ways that won’t work.” - Thomas Edison