How does Jerry Spinelli use imagery in Loser?

Imagery:

"This is how Zinkoff at the age of eight imagines the inside of his head: a moving part, like an elbow or knee"

"He knows that if he ever springs a leak or throws a gasket, his dad will be there with duct tape and chewing gum to patch him up, that no matter how much he rattles and knocks, he'll always be a honeybug to his dad, never a clunker."