Imagery and symbolism are similar literary devices in that they both provide a picture of something. What underlies imagery and symbolism is visibility. For imagery and symbolism to function, there must be something that can be seen. Imagery and symbolism are different because not all images necessarily carry a deeper meaning. In a certain light, symbolism can be thought of as multilayered imagery. There’s the image itself, then there’s the hypothetical concept or idea behind that image.

In Emily Dickinson’s poem “I heard a Fly buzz—when I died—,” the fly is visible. One could say that Dickinson uses fly imagery. It’s also possible to state that the fly represents a broader idea, like the unglamorous aspect of death. Now, the fly has become a symbol. Similarly, there’s the basic image of people waiting for the king to enter the room, as well as the potential for the king to symbolize an abstract concept, like the end of one's life.

Sometimes, the difference between imagery and symbolism can be perplexing. One might wonder why the fly just can’t be a fly or the king just can’t be a king. In a sense, the difference between imagery and symbolism depends on the reader. They must use their critical faculties to argue why particular imagery can be a symbol, or why select imagery is just imagery.