Throughout the first chapter of this novel, Ray Bradbury employs some sort of imagery on nearly every page. However, most of this imagery is aimed at proving a contrast between Montag's world—the world of the firemen—and Clarisse's world. Bradbury employs his imagery by using a series of metaphors and extended metaphors.
One of the most obvious ways Bradbury employs imagery in this chapter is by the constant comparison of those in the firemen's world to insects or serpents. The novel begins with a very vivid description of the firemen burning down a house with "the great python spitting its venomous kerosene upon the world." Then, as Montag watches the house that was full of books burn, he "strode in a swarm of fireflies." The metaphors continue as Montag compares the mechanical hound that is a stand-in for the traditional firehouse's dalmatian to "a great bee come home from some field where the honey is full of poison wildness, of insanity and nightmare..." and later to "a moth in the raw light, finding, holding its victim, inserting the needle..." Even in it's actual description the hound sounds like a giant spider: "[T]he Hound had sunk back down upon its eight incredible insect legs."
Montag's world extends beyond the dangerous, insect-ridden firehouse to a cold and dark home life. When Montag comes home after his first interaction with Clarisse, he walks into his home and compares it immediately to a "mausoleum after the moon had set." He goes on with a vivid description of his home:
"Complete darkness, not a hint of the silver world outside, the windows tightly shut, the chamber a tomb-world where no sound from the great city could penetrate."
Bradbury then continues with the insect imagery by comparing the music coming from his wife's Seashells (what we would call earbuds) being called "mosquito-delicate" with an "electrical murmur of a hidden wasp snug in its special pink warm nest."
Meanwhile, the world Clarisse shows Montag is beautiful and slow. Twice in the chapter, Montag compares his wife to a praying mantis, but in this chapter, he says Clarisse's face is like that of a clock in the middle of the night:
"[Y]ou waken to see the time and see the clock telling you the hour and the minute and the second, with a white silence and a glowing, all certainty and knowing what it has to tell of the night wiftly on toward further darknesses but moving also toward a new sun."
In addition, Clarisse provides several strong images to Montag at the beginning of the book that contrasts the insect-filled, fast world. She tells him that "there's dew on the grass in the morning" and "...if you look ... there's a man in the moon."
Bradbury provides all of these images as a way to provide contrasts between the two worlds and to indicate that the world run by the firemen is a cold, fast, insect- and serpent-filled one, while the world of books is slow and timeless.