For the Slideshow option on Desktop Settings / Wallpaper, and the user is using the Random order and a new file appears in one of the wallpaper folders, make that image the next one to show.

Thanks for the hint Chloe ! I created a new bugtracker bug but I was unable to find a “Plasma Workspace Wallpapers” section. https://bugs.kde.org/show_bug.cgi?id=476909

I hope I was able to give them enough info…