A fun question. Poe used images throughout the story to characterize the narrator. A few examples can be seen below.
In the first few lines, the narrator uses many images (heaven, hell, etc.) to indicate the breadth of his senses; this also shows his unbalanced mind.
When the narrator describes the eye of the old man, he uses images that show his obsessive nature, as well as his unbalanced perspective. (The "eye of a vulture"!)
At the story's end, when he gives himself away, the images of the sounds heard indicate how nervous and explosive the narrator is becoming.