How does Orson Scott Card use imagery in Ender's Game?

Examples of Imagery:

"Bonzo's tight, hard ribs came against Ender's face, and his hands slapped against his back, trying to grip him."

"It wasn't a dark game, but it wasn't a bright one either - the lights were about half, like dusk."

"What could be torn by the small scavengers was torn; the maggots had done their work on the organs; now it was a desiccated mummy, hollowed-out, teeth in a rigid grin, eyes empty, fingers curled."