The image wallpaper is a mess of 4 different fade functions, some not in
sync, and very complicated swapping images about.
This simplifies the whole thing by using a StackView, we just pop our
setup with a new configuration on and it handles deleting old objects
when the transition ends.
Code is 1/3 the size, whilst doing the same thing and should result in
having fewer items about.
In addition with this patch changing the transition effect in future
would be super trivial.