"What does it mean for something to be Earth's size, scaled appropriately? Isn't it just... smaller than Earth?"
"If it were a picture of Earth, wouldn't you say it was appropriate to say it was a picture of a planet with Earth's size and rotation speed?"
"Uh, I wouldn't say it that way, any more than I would bother to mention that a photo of me is a photo of someone who is my size. And this planet isn't a real planet somewhere, right? Maybe you're cashing out rotation speed as a miles per hour thing instead of a revolutions per day thing...?"
"It's an imaginary planet, but size is still an attribute planets have, even when they don't physically exist. I'm not an artist; I didn't imagine this picture and then decide it should display planetary rotation. I imagined a set of characteristics for a planet, and then I had the magic generate an appropriate image. If I'd imagined a planet the literal size of the picture on the cover of this book, it would be a lump of rock, or maybe a neutron star."
"Okay," shrugs Aurora. "Well, that's my profile - nice revisions, Glass." And she wanders off.