How does Laurie Halse Anderson use imagery in Wintergirls?

Imagery:

"Yesterday's dirt and mistakes have moved through me. I am shiny and pink inside, clean. Empty is good. Empty is strong."

"We held hands when we walked down the gingerbread path into the forest, blood dripping from our fingers. We danced with witches and kissed monsters. We turned us into wintergirls, and when she tried to leave, I pulled her back into the snow because I was afraid to be alone."