Setting a Representative Album Card
Enter the album card management page.[Enter album > top album card area] OR
[Album management page > Menu on the right side of the album > 'Manage album cards'].
Touch "Set as main card" below the card you want to designate as the representative card to finalize the change.
You can choose a representative card only from the album cards you have collected.
You can see the album card change on the home screen and on the album entry screen.