Too much causes paper to bruise and crack. Of Speculation makes a great thumbnail because the puzzle engages our human need to solve. It also strategically anonymizes the doctor on the cover to make the book more universal.
Paper can only absorb a limited amount of ink. It also helps to keep your colours simple. Visual communication in part or whole relies on eyesight. A nice take on a traditional still life composition. With print however, things arent so simple and you need to keep an eye on the on the total ink coverage youre putting down. After gathering enough information it is time to start laying it out and filtering through it all. This shouldnt mean different images for both versions, but you should tweak some elements to better suit the format.