Plex just today has allowed local assets to be used for the “new” SquareArt backgrounds that are used for the mobile UI. This finally allows users to fix the cropped backgrounds that a lot of media had. Unfortunately infuse does not use those SquareArt assets for its mobile app, instead it still uses the generic background asset that (most of the time) gets cropped.
How it looks in Plex using the SquareArt:
How it looks on Infuse, which is still using the Plex background asset:
The selection on Plex looks like this:
