Hughes' first two images depict withering and drying, a sense of death. His first example, a "dried raisin," conveys that the dream deferred has shriveled into nothing and has no hope of ever happening. The dried raisin, being old, wrinkled, and lifeless, suggests that the dream deferred is forgotten, lost, and nothing but a memory. The second example, crusted syrup, being hard and dried up, again suggests that the dream deferred has no life. Also, being bittersweet, using the example of syrup implies that the dream deferred is hard and sour (undesirable) on the outside, yet sweet on the inside.
The next two images Hughes uses continue to suggest a sense of death and decay. The first, "rotten meat," which is odorous and reeks of death, very strongly suggests that the dream deferred has lost its beauty. This image also implies that the dream is a thing of past that's now worthless. The second image, a "running sore," hints that the dream is synonymous to a diseased, infected wound. The dream has now become grotesque, ugly, and painful. Also, since a sore can be irritating and bothering, we can deduce that the dream deferred keeps nagging at the person. This prevents the person from ignoring or forgetting about their dream.
The following image, which compares the dream to a sagging, "heavy load," shows how burdensome it can be. It's as though the memory of the dream is in the bag, and the disappointment of the dream's impossibility weighs the dreamer down. The dream deferred (bag) is very heavy and onerous. However, if the dreamer carries the bag long enough, they get to enjoy the reward (their dream) waiting inside.
The final image used to describe a dream deferred is an explosion. The worsening conditions in Hughes' comparisons build up to the final dénouement of a violent explosion. This "explosion" is all of the pent up emotions, thoughts, and feelings of the dream deferred, which build up inside you until, finally, they are expressed all at once in one big eruption.
Throughout the poem "Harlem," Langston Hughes wrote with increasingly destructive images to warn of the dangers of postponing your dreams. These images help present the poem's very strong message that a dream deferred can be very painful. The thought of how great the dream is nags at the dreamer's mind until they can no longer bear it. The "explosion" result of this pestering dream deferred can actually be good for the dreamer. The dreamer may keep trying even harder to break through the obstacles to finally achieve their dream. Once they overcome these hindrances they will see how happy their dream makes them. After their success they will be glad they persisted at trying to achieve their dream deferred.