A recent blog post ("I've Never Been There But I Have Seen the Stone") discussed sketches of tombstones that appear in a Sargent genealogy from 1895. This book is available digitally in at least two locations, the Family History Library's website and Archive.org. Any citation to the digital form of the book should indicate the actual site from which it was obtained.
The pictures of the tombstones that were used to illustrate the blog post appear on a page originally inserted between pages 32 and 33. This page (and the blank one preceding it) are shown in these two illustrations from Archive.org's "page turner" viewing option.
The first screen shot shows page 32 and the "blank" page on the right. The blank page on the right is actually the back side of the page that has the pictures. Typical for the era, pictures were printed on pages that often did not have text on the reverse.
This set of images shows page 33 on the right and the un-numbered page that contains the tombstone images.
The image below comes from the PDF version of the book that was made from the item in the collection of the Family History Library. The view was made in Adobe Acrobat. There is nothing between pages 32 and 33. The picture either was removed from the book by a patron before digitization or it was missed. I am suspecting the latter.
Not all digital versions may be created equally. Cite your sources.
This makes me think that there might even be justification for including which facility was used to reference a printed book as well.