cover-bound

[maiabulela]

The photographer was shooting (Ashly Simpson and Jessica Simpson) for a magazine cover. He said:

"It was not meant to be a double cover, but they turned out beautifully together"

Then the announcer said: That they were cover-bound.

Photographer: The pic is nice and their mom loves it.

What's The meaning of (cover-bound) here??!!! I mean there is not specic context, they were just talking. Can you give me any suggestion?

[Anglika]

It means that the photos are clearly going to be used on a magazine cover.