Background: don't lose someone's wallpaper if the set it was chosen from is updated
Distros typically install a set of wallpapers that someone can choose from. Sometimes those sets need to be updated, because they get stale and outdated.
However, this can create a problem: if someone upgrades their distro and the wallpaper set is updated, the user can lose the wallpaper that they have chosen. Obviously people don't like this - if they've picked a wallpaper, they want to keep it until they choose another.
It would be great if the control center could handle this situation. Perhaps it would be possible to cache the selected wallpaper in the user's home directory, so there's a copy that's always available?