A powerful, if rather unpleasant example of imagery that Poe incorporates into “The Black Cat” is that of Pluto hanging from the tree in the narrator's garden.
The image becomes particularly powerful when we're told that the cat hangs at night when the narrator goes to bed. This really drives home the horror of this profoundly disturbed man's actions and adds to the generally grotesque atmosphere of the story.
A further powerful use of imagery can be seen when the narrator claims to be able to see an image of the gallows on his second cat's fur. A gallows, of course, is an apparatus for hanging people, and so it's not surprising that, in his feverish state of mind, the unreliable narrator should see a symbol of his killing of Pluto etched into the fur of his latest pet.
As well as being horrific and grotesque, this particular image acts as a physical manifestation of the narrator's guilt over killing his once-beloved cat. As a psychoanalyst might say, he's being tormented by his guilt complexes.