How does James M. Cain use imagery in Double Indemnity?

Imagery:

"But all of a sudden, she looked at me, and I felt a chill creep straight up my back and into the roots of my hair."

I took one of the crutches and hooked it under his chin. I won't tell you what I did then. But in two seconds he was curled down on the seat with a broken neck, and not a mark on him except a crease right over his nose, from the crosspiece of the crutch.