What should be on the SD card that goes in the back of my DS

I was upgrading to Pikes Peak and decided to do some house keeping on the SD card. What, if anything, needs to be on the SD card? The unit used to need the SD card to properly display artwork, does it need some specific file?

No files need to be on the card.

But it does need a card inserted to display artwork when using the Bridge input. The card can be blank when inserted and the artwork file will be recreated.