It really is, considering the number of people who use Amazon's affiliate service. She's not sneaking in links or using a URL shortener or something. She's taking a part of her review that might entice people to buy the book— the illustrations— and adding an affiliate link to them. Pretty mundane. Personally, it just hasn't crossed that line into "shady behavior used by spammers."

Er, no. I'm not saying those images exist solely to entice someone into clicking them. That would be advertising.

Those images fulfill a purpose to the reader: They deepen the review.

In what way does an affiliate link deepen the review?

They don't. The images do. She is merely utilizing the images to also be affiliate links.

What "merely"? That's exactly what I said she was doing.