As a rule, (who's rule I am not sure) an object's directionality determines its placement. For animals and humans that would be the way the eyes are looking, they should always be looking into the center spine except for the cover where they should be looking to the right and into the book's opening. For objects, if there is a shaded or darker side that side should be closer to the outer edge of the page and on a cover the darker side should be on the left. As for background imagery if there is a darker side or a side with tall items it should be at the page edge and not the center spine. This may help narrow down possibilities.
As a rule, (who's rule I am not sure) an object's directionality determines its placement. For animals and humans that would be the way the eyes are looking, they should always be looking into the center spine except for the cover where they should be looking to the right and into the book's opening. For objects, if there is a shaded or darker side that side should be closer to the outer edge of the page and on a cover the darker side should be on the left. As for background imagery if there is a darker side or a side with tall items it should be at the page edge and not the center spine. This may help narrow down possibilities.