How does Edgar Allan Poe's vivid imagery influence his writing?

Poe's imagery clearly has a great impact on his writing,
as so much of his work is dominated by the bizarre, other-worldly contexts he sets his
characters and stories in. An excellent example to focus on would be "The Fall of the
House of Usher," which begins with an excellent example of Poe's imagery that creates a
fantastical Gothic landscape, which of course foreshadows the terror and mystery of the
story itself. Note how Poe uses his vivid imagery to create an unmistakeable atmosphere
of oppression and gloom in the following example:

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During the whole of a dull, dark, and soundless
day in the autumn of the year, when the clouds hung oppressively low in the heavens, I
had been passing alone, on horseback, through a singularly dreary tract of country; and
at length found myself, as the shades of the evening drew on, within view of the
melancholy House of Usher. I know not how it was--but, with the first glimpse of the
building, a sense of insufferable gloom pervaded my
spirit.

Note how the imagery,
combined with the alliteration of "dull" and "dark," creates a real mood of depression
and gloom. The clouds hang "oppressively" and the narrator is passing through a
"singularly dreary tract of country." The House of Usher is described as "melancholy"
and is seen at dusk. Upon seeing it, the traveller is filled with a sense of
"insufferable gloom."

Really, so many of Poe's descriptions
could be used as textbook illustrations of how to create Gothic imagery, and the example
above is almost flawless in the way that Poe's vivid imagery is used to present us with
terrifying landscapes of the imagination .