How does Terry Brooks use imagery in A Knight of the Word?

Imagery:

"There, in the warm enfolding dark, just before she fell asleep, with the images of Ariel and Boot and Audrey spinning in a wash of streetlight shining brightly through her bedroom window, she made herself a promise that she would see this matter through to the end."

"Pick, her best friend, was a six-inch-high sylvan, a forest creature who looked for the most part like something a child had made of the discards of bird's nest, with body and limbs of twigs and hair and beard of moss."