What kind of imagery does the poet use, and what effect does it have?

"The Raven" is a critically-acclaimed poem by Edgar Allen Poe. When the poem was published in 1845, it immediately became popular among the public due to its hypnotic cadence and dark but interesting imagery. The publication of "The Raven" boosted Poe's writing career—who was living in dire poverty at the time—and made him a household name.
Poe uses vivid imagery in "The Raven" that was inspired by the Gothic literary tradition, which first became popular in the 1700s. The most persistent image throughout the poem is the titular raven itself. The raven is symbolic of bad omens and the nightmares of his personal past. Much of the poem—like many poems during Poe's time—was filled with symbolism.
Symbolism itself, by its very nature, is dependent on imagery, especially in the poetic medium. The most blatant theme in "The Raven" is the feeling of guilt by the narrator. In Poe's fiction and poetry, a supernatural haunting usually symbolizes persistent psychological trauma.
The image of the narrator alone in a large, dark mansion symbolizes loneliness and, perhaps, alienation. It could also be interpreted as the narrator imprisoned in his own mind, with the mansion symbolizing his psyche or cranium.
The cliche imagery of the stormy night is effective in "The Raven" because it sets up the mood and atmosphere of the poetic narrative. Like the ebony-colored raven, the pitch black night sky and storm clouds all convey a sense of darkness.