Thank you! For the past couple of years I've been using Kuvva.com to do this: in addition to having a nice selection of wallpapers their Mac app also correctly

Thank you! For the past couple of years I've been using Kuvva.com to do this: in addition to having a nice selection of wallpapers their Mac app also correctly keeps the wallpaper the same on all monitors/spaces. But with this gem I can use my own desktop pictures and still have consistent images across virtual and physical screens!