Let's pretend the art books exist in-universe as scrapbooks put together by Mako (since she seems like the one who'd be most likely to take on a project like that). All the illustrations are thus actually photographs or collages the characters have taken/assembled. For this thought-exercise, pick an illustration and come up with an in-universe explanation for it.
I'll start:
This photo was obviously used for the cover of Vogue Japan when Haruka and Michiru publicly came out as a same-sex couple. Other cover stories included A Day in the Life of Princess D, an investigative piece on the mania surrounding the Silver Crystal, and a retrospective on the career of missing idol Pandora.
I'll start:

This photo was obviously used for the cover of Vogue Japan when Haruka and Michiru publicly came out as a same-sex couple. Other cover stories included A Day in the Life of Princess D, an investigative piece on the mania surrounding the Silver Crystal, and a retrospective on the career of missing idol Pandora.