I can't see anyone else on the forum with this issue so maybe I'm just megadumb, but I've got a number of 21:9 wallpapers at 3840x1080 which I cannot get to display continuously over my two screens. Instead I get half of the wallpaper duplicated on each.
There are no controls for this in the GUI that I've found. Is there any equivalent to the 'tile' function for Windows desktop wallpapers?

    trenchanter I cannot get to display continuously over my two screens

    That's not 21:9 it's dual screen, search for that and to make it short Budgie has no multi monitor support.