While William Shakespeare's play Hamlet is set hundreds of years before George Orwell's novel 1984, the two works do share several common themes. One of those themes, as you mention in your question, is reality versus unreality. Both Winston and Hamlet struggle with this idea, though it shows up differently in each work.
Winston's troubles with reality all stem from the Party and Big Brother. Because the Party changes, edits, and even rewrites truth to suit its current needs, Winston never really knows what is real and what is not. Even the language (doublespeak) plays a role in disguising truth.
Some potential images which might depict Winston's struggle between reality and unreality might be based on three three quotes from the novel.
- “It was a bright cold day in April, and the clocks were striking thirteen.” How about a clock face with thirteen numbers on it.
- “Big Brother is Watching You.” Perhaps a billboard (or some other large image) depicting Big Brother, the real face of unreality.
- “Doublethink means the power of holding two contradictory beliefs in one's mind simultaneously, and accepting both of them.” Picture two "thought bubbles" above a head or maybe one face with two profiles.
Hamlet's struggle is a little different, but he, too, must try to determine what is real and what is not in what was once his familiar world. In fact, the readers have the same struggle as we follow Hamlet's journey of revenge. He warns his friends he will be putting on an "antic disposition" and we know Hamlet is an actor. How much, if any, of what he does is real madness, and how much is feigned madness as part of his unnamed plan to seek revenge for his father's murder--that is what we do not know, and perhaps Hamlet does not, either.
The most apt symbol for this struggle is, of course, the drama masks. It suits the theme of reality and unreality as well as the concept of Hamlet's acting mad. These two quotes work with the mask idea:
Make you to ravel all this matter out:That I essentially am not in madnessBut mad in craft.
God hath given you one face, and you make yourself another.
“I am but mad north-north-west. When the wind is southerly, I know a hawk from a handsaw.”