In Windows 10, wallpaper personalizations are harder to access (especially if you want to put a different wallpaper on each monitor). Harder, but not removed. Under a command prompt (Win+r "cmd"):

control /name Microsoft.Personalization /page pageWallpaper

And you can tweak wallpapers to your heart's content.

Working often on Windows in $dayjob, I guess it was only time that I put Windows-related stuff in this blog -_-