How does Michael Morpurgo use imagery in Waiting for Anya?

Examples of Imagery:

"And even then they respected him and not just for his size but because Hubert was always game—he would always join in whatever was going on. He was like a chameleon; whatever they were—pirates, soldiers, Red Indians—he would be too."

"And then he saw the girl. She was walking towards him. She had red hair that she pushed back out of her eyes and tucked behind her ears. 'I'm Anya,' she said."

Rouf was the kind of dog that didn't need to bark too often. He was a massive white mountain dog, old and stiff in his legs but still top dog in the village and he knew it. He was barking now though, a gruff roar of a bark that woke Jo instantly. He sat up. The sheep were gone. Rouf roared again from somewhere behind him, from in among the trees. The sheep bells were loud with alarm, their cries shrill and strident. Jo was on his feet and whistling for Rouf to bring them back. They scattered out of the wood and came running and leaping down towards him. Jo thought it was a lone sheep at first that had got itself caught up on the edge of the wood, but then it barked as it backed away and became Rouf — Rouf rampant, hackles up, snarling; and there was blood on his side. Jo ran towards him calling him back and it was then that he saw the bear and stopped dead. As the bear came out into the sunlight she stood up, her nose lifted in the air. Rouf stayed his ground, his body shaking with fury as he barked.