How does Suzanne Collins use imagery in Mockingjay?

Collins uses detailed physical descriptions to not only illustrate her characters, but to expose their personalities as well.

“But not Alma Coin, the president of 13, who just watches. She’s fifty or so, with gray hair that falls in an unbroken sheet to her shoulders. I’m somewhat fascinated by her hair, since it’s so uniform, so without a flaw, a wisp, even a split end. Her eyes are gray, but not like those of people from the Seam. They’re very pale, as if almost all the color has been sucked out of them. The color of slush that you wish would melt away”