How does Bernard Cornwell use imagery in The Winter King: A Novel of Arthur?

Imagery:

Norwenna's screams became fewer, but her whimpering more desperate until at last Bishop Bedwin's wife came from the hall and knelt shivering beside the High King's chair.

"She kissed the sword as she had been commanded, and just as her lips touched the grey steel, Gundleus rammed the blade hard down. He was laughing as he killed his bride, laughing as he slid the sword down past her chin into the hollow of her throat and still laughing as he forced the long blade down through the choking resistance of her writhing body. Norwenna had no time to scream, nor any voice left to scream with as the blade ripped through her throat and was rammed down to her heart.