How does George MacDonald Fraser use imagery in Flash for Freedom!?

Imagery:

I've always been big and hearty and looked the kind of chap who'd go three rounds with the town tough if he so much as stepped on my shadow, and from what Tom Hughes has written of me you might imagine I was always ready for devilment. Aye, but as I've grown older I've learned that devilment usually has to be paid for.

Row upon row of black bodies, packed like cigars in a box, naked and gleaming, the dark mass striped with glittering dots of light where the eyes rolled in the sooty faces. The crying and moaning and whimpering blended into a miserable anthem that I'll never forget, with the clanking of the chains and the rustle of hundreds of incessantly stirring bodies, and the horrible smell of musk and foulness and burned flesh.