[Feature Request] Ability to change the background for fullscreen independently from the main cover art

[JanluOfficial]

Currently, the cover art and full screen background is the same, which makes it looks like this.

I would like to be able to set a different background image for each song, as (at least for my own), I always export the cover art in both 1:1 and 16:9. Just for an example, here's the 16:9 version of the cover for "Different"

Setting this as the background would look so much nicer compared to the stretched cover art.