i had 1 book with pictures too--and pretty glad it was only one, because those pictures were pretty horrible...
actually, you might be right about the variation--for book 1, i heard several different versions, but the last book it seemed almost everyone had the same. i guess they couldn't come up with more brilliant pictures than those 🙄
but the first book, the variations were huge--i thought had a pretty decent one, after a friend of told me he had like 20 questions on worms in his!!!
i just think that it would be a tad hard to cheat off of someone in class. and a little too bold to use other methods.