How does Ivan Doig use imagery in This House of Sky: Landscapes of a Western Mind?

Imagery:

"She would sniff the baby imposter endlessly, distrustful but pulled by the blood-scent of her own" (p. 163).

"Then ewe and lamb were each stamped, in blotty digits about 5 inches high, with a number that showed they belonged to each other" (p. 162).