How does Stephen King use imagery in The Dark Tower VII: The Dark Tower?

Examples of Imagery:

"Standing up straight on her stumps, Susannah spread her arms, Roland's pistol clenched in her right hand, and made a Y against the sky. Then she screamed. There were no words in it, nor could there have been. Our greatest moments of triumph are always inarticulate."

"The man floated to his fate, shrieking and eyeless. He thrust his hands out in front of him, making warding-off gestures, and the spider's front legs seized one of them, guided it into the bristling maw of its mouth, and bit it off with a candy-cane crunch."