Adding other Photos to a Book Project

[Eric]

For fun, I added some other pics and art I've contracted for this book into GR. When I look at this from a friend's phone, etc, I can't see the other art. I'm very new to GR and I'm still a bit lost in the details... so forgive this question if it's overly noobish, but what is the point of adding other art if it's not visible to readers? Alt question - is there something I need to do to make it visible besides just including it?

[rivka]

The other images are visible from the desktop, but not from the mobile site. I can see them just fine.

Please also note that covers should not be added to the other images section.