How does the author use imagery in the novel, Odd One Out?

Imagery can be seen in Coop's description of Jesse as “Jesse Cox, power forward - better known as Golly since he’s a certifiable giant but Goliath is too hard to chant” (15). Later he explains that Jesse is "six foot seven and 240 pounds of mahogany steel but has this high-pitched hyena giggle” (18).