How does Vladimir Nabokov use imagery in Lolita?

Imagery:

"I groped for the timetable I had in my pocket and surreptitiously fished it out to look as soon as possible for a train. I was still walking behind Mrs. Haze through the dining room when, beyond it, there came a sudden burst of greenery - 'the piazza,' sang out my leader, and then, without the least warning, a blue sea-wave swelled under my heart and, from a mat in a pool of sun, half-naked, kneeling, turning about on her knees, there was my Riviera love peering at me over dark glasses."