How does the sum total of all of the imagery add up to answering the question put forth by the speaker in line one, “What happens to a dream deferred”?

Langston Hughes uses the elements of imagery and rhetorical question to foreshadow the destructive consequences of unfulfilled dreams. Particularly, the dream in question, and the subject of his poem, is the dream of survival, freedom, and personal happiness for all African Americans who are still living under oppressive circumstances.
Langston Hughes's poem is filled with dark images of decay and destruction. He uses a series of similes that compare dreams to raisins that "dry up," sores that "fester" and "run," and "rotten meat" that "stinks." He speaks of syrup that "crusts over."
Then he hints at the physical exhaustion that comes from one not fulfilling one's dreams when he uses the simile "it just sags like a heavy load."
The comparisons he makes are phrased in the form of rhetorical questions. This means that the speaker is not really asking a question, but making a point. His point becomes most clearly made in his final question, "or does it explode?"
Hughes's last question presents many destructive possibilities. These possibilities are in fact the answer to the central question that the poem poses. One is that African Americans will self-destruct by actions that harm themselves and their individual lives and neighborhoods. Another, more violent possibility is that African Americans will rebel and do whatever it takes for society to give them the freedoms and chances for opportunity that they truly deserve. The idea of an explosion seems to imply that these actions may involve bloodshed, violence, or destruction.
While the poem is generally understood in a civil rights context, if one takes the poem as a statement on humans as a whole, it seems to say that each individual needs the rights and abilities to pursue their own aspirations and lead their best life. When these possibilities are denied, catastrophic consequences will follow.