Business and the chocolate factory
The question of imagery is a major consideration in this novel, because Nabokov is a true genius: he weaves objective reality into the details of the prose that Hermann Karlovich ignores or pushes to the side. He is constantly denying the facts, speculating wrongly about reality, and making himself out to be more powerful and correct than he is. His subjective opinion about himself is shown in the imagery of his business success. As the owner of a chocolate factory, he feels authoritative and powerful.
The ignored imagery of Lydia's affair
Then, all the sudden, Hermann walks in on his wife having sex with her own first cousin. He has just spent the first portion of the novel explaining why his wife worships the ground he walks on. Clearly, this imagery is evidence that he is wrong about his feelings of superiority, right? He cannot continue believing that his wife is a doting, faithful wife when he watched her rolling around naked with another man, right? Well, that is the value of this imagery. By seeing Hermann ignore the facts about reality that disagree with his delusions, the imagery of the affair becomes evidence of his intentional ignorance.
Appearance and perception
The imagery of how things appear to one's perception is certainly close to the thematic center of the novel, but perhaps most important of all the imagery of this kind is Felix. Because of the interactions Hermann has with Felix, the reader learns about his experience of perception. We learn that he projects himself onto other people. He literally projects his own perception of self onto Felix, claiming that they are exact look-alikes. Are they really? The police easily see the difference, so the perception is obviously wrong. Felix himself claims not to see any resemblance.
Murder and tragic downfall
Hermann does not know he is in a tragic spiral until it is too late. His delusional grandeur and his emotional commitment to always being right despite evidence—those are a specific kind of pride. They are a pride historically called "hubris." This hubris refers to a man's emotional suspicion that he is above fate, or that he is above fate somehow. This is a signal that a reckoning is coming with some sort of tragic downfall. In Hermann's case, this all happens through literal imagery; he is found guilty of murder by the police when he thought for sure he was going to get away with it. A judgment against his character is easily deduced from that imagery.
