It would be nice if there were an option to synchronize the wallpaper and lockscreen so that they are the same image, plain color, etc. This is a feature available on smartphone OSes and other DEs.
A very common request. I think we should do it--as long as it's a non-default, user-initiated action.
That would be nice since it saves the user time who wants to keep them in sync. Ideally, it would also allow for syncing of the SDDM background, but I suppose that is not an option.
Maybe here can be a checkbox on SDDM and lock screen background configuration: [ ] Use the same picture as wallpaper. By default, it should be unchecked. If checked, wallpaper (if it is picture, not some OpenGL animation, etc.) will be applied to SDDM and lock screen. When user changes wallpaper, SDDM and lock screen background also changes.
*** This bug has been marked as a duplicate of bug 367666 ***