How does Steven Levenkron use imagery in The Best Little Girl in the World?

Imagery:

"She was fat. Worse than that, she was a monster. A five-foot-four-ninety-eight-pound monster."

"The girl was horribly thin, and her clothes hung on her as they would on a hanger. As the girl passed her, she looked curiously at Kessa, but Kessa kept her eyes fixed straight ahead. The girl was obviously what the nurse's aide called a skinny, and Kessa couldn't stand the sight of skinnies."