At the beginning of Chapter 3, Scout uses vivid visual imagery to describe her classmate Walter Cunningham. He is from a poorer family than hers: one can clearly tell by looking at the boy that he is malnourished.
Walter looked as if he had been raised on fish food: his eyes, as blue as Dill Harris’s, were red-rimmed and watery. There was no color in his face except at the tip of his nose, which was moistly pink. He fingered the straps of his overalls, nervously picking at the metal hooks.
Using imagery, Scout compares Walter’s diet to fish food—something that would have little to no nutritional value for humans. Walter was raised in a food-insecure household, and he looks it.
This excerpt and the accompanying imagery speak volumes about Scout’s maturity at the beginning of the novel. She is still young, with a lot of learning to do, and clearly lacks empathy for her classmate. Instead of attempting to understand Walter’s perspective, she judges him, treating him as lesser than herself. It is a testament to Scout’s growth, both throughout the novel and as an adult narrator, that she becomes an empathetic person, driven by justice rather than judgement.
In Chapter 3, Atticus provides Scout with some sage advice about empathy, utilizing a key metaphor in his analogy:
Atticus stood up and walked to the end of the porch. When he completed his examination of the wisteria vine he strolled back to me.
“First of all,” he said, “if you can learn a simple trick, Scout, you’ll get along a lot better with all kinds of folks. You never really understand a person until you consider things from his point of view—”
“Sir?”
“—until you climb into his skin and walk around in it.”
The imagery of "climbing into [someone's] skin" is incredibly important in To Kill a Mockingbird, representing the vision of empathy and consideration Atticus wishes to impart to his children. This conversation with Atticus is thus a key teachable moment for young Scout, who must learn to think outside of the self-centeredness that comes naturally to humans. The image of "climb[ing] into" someone's "skin" is clearly figurative; Scout knows that no one can literally do that. But Atticus's use of this imagery gets across what he wants Scout to understand—that empathy must go more than skin deep, and it involves a genuine effort to understand what another person's experiences are like for them.
While this singular moment in the novel represents an important thematic coalescence, it is by no means the only place in which Atticus attempts to teach Scout about empathy. She must learn, as anyone must, through repetition and practice. She learns slowly, through gradual exposure to the world’s problems.
In the following passage from Chapter 4, Scout describes the drama that she, Dill, and Jem made up about Boo Radley. The imagery she chooses to implement in her description is notable:
It was a melancholy little drama, woven from bits and scraps of gossip and neighborhood legend: Mrs. Radley had been beautiful until she married Mr. Radley and lost all her money. She also lost most of her teeth, her hair, and her right forefinger (Dill’s contribution. Boo bit it off one night when he couldn’t find any cats and squirrels to eat.);
Imagery is used in this excerpt to portray Boo as some kind of animal, compelled to eat raw cats and squirrels. This portrayal by Scout reflects the children's attempt to process and understand abnormal behavior—both that of Boo's parents and Boo himself. Unfortunately, in their attempt to process a confusing situation, Scout, Jem, and Dill end up dehumanizing Boo and his whole family, placing them on the level of animals. In doing so, they fall back on the assumptions that have been modeled for them by adults: namely, that all mentally ill or otherwise abnormal people are by default violent. This violence is connected to the dehumanizing animal comparison, implying that Boo and his family are too far from human to exercise restraint.
In Chapter 9, Scout stands up for herself, fighting her cousin when he insults Atticus. When Uncle Jack, believing that she was bullying her cousin instead of defending her father, tries to punish her, Scout runs away. The imagery in this scene provides important characterization for Scout:
I was debating whether to stand there or run, and tarried in indecision a moment too long: I turned to flee but Uncle Jack was quicker. I found myself suddenly looking at a tiny ant struggling with a bread crumb in the grass.
This "ant in the grass" imagery represents Scout's feelings of frustration and helplessness in her present situation. She feels the full weight of adult injustice, feeling that she is being wrongfully punished for doing the right thing and standing up for Atticus. When the adults around her (i.e., Uncle Jack and Aunt Alexandra) interpret her righteous anger simply as temperamental behavior, Scout feels ignored and misunderstood. This misunderstanding is important not only as a window into Scout's character, but as a representation of the novel's themes. Children are often willfully misunderstood or sidelined by adults, and they feel this disregard keenly. Scout's frustration as an "ant in the grass" is the kind many children feel deeply.
In the following passage from Chapter 21, Scout describes the atmosphere in the courtroom using imagery to compare it to a "cold February morning."
It was not unlike one I had last winter, and I shivered, though the night was hot. The feeling grew until the atmosphere in the courtroom was exactly the same as a cold February morning, when the mockingbirds were still, and the carpenters had stopped hammering on Miss Maudie’s new house, and every wood door in the neighborhood was shut as tight as the doors of the Radley Place. A deserted, waiting, empty street, and the courtroom was packed with people.
Scout conjures up the expectant air in the courtroom through her description of a cold morning: everything is still, either sleeping or waiting for the dawn to break. Similarly, those in attendance wait in anticipation of a decision, on the edge of something like one of those cold winter mornings.
The imagery in this scene also foreshadows the jury's decision to convict Tom Robinson, creating an expectant air of dread. Lee doubles down on this imagery, deliberately choosing a "cold" morning as the example in this passage. The effect that the court decision has on the spectators, the imagery implies, will be a chilling one.