This is one of those things that has proven difficult to google for. I only find people asking about how to get boxart in general.
I’ve been looking for a way to get the boxart to become the actual icon for the content in the playlist, instead of the generic cartridge icon.
I’ve come to believe that this is currently not a feature, but I also think that it’s strange that no one has asked about/suggested this before.
I’ve created a mockup of what I mean below. It’s basically how the PS3 XMB menu worked. The exact scaling/spacing can be discussed of course. This is just to illustrate the point.