X Add MacOS support
X Add Windows support:

Add non Plasma Linux desktop support:
    https://stackoverflow.com/questions/1220826/changing-wallpaper-on-linux-programmatically
    https://github.com/GNOME/gthumb/tree/d644a77a1b2085ce2c947719fb3f9107e068c42c/extensions/desktop_background

Add wallpaper layout and position settings support (require to write a plugin dialog).

Add wallpaper Slideshow mode support to export album contents:
    https://bugs.kde.org/show_bug.cgi?id=285888