Time and death
The girl in the first story, the title story, is asked a difficult question every day. Why does she live the way she lives? How long will she live in the restrictive, sheltered mode her parents told her to? Then, the stories quick-cut to the next story, showing sex from the end, not the beginning. What is implied is the imagery of time. The instant transition from a young girl losing her virginity to the man mourning his dead wife is an invocation of the abstract imagery of time. This is the basic depiction of the imagery, which then appears in various permutations and variations throughout the other stories.
Sex and love
As mentioned, sexual imagery also appears in the stories, but it isn't just erotic moments. There are a few romantic moments, but actually, sex is explored through negative imagery. We see the outcome of mating with the wrong person in "Scary," in "A quick one," and then in "A story of folding and unfolding," the reader sees sex through negative imagery again—the lingerie reminds the man through arousal of the love he lost; his dead wife is a ghost who haunts him through sexual desire. The imagery of sex is quite unnerving and otherworldly.
The public
The stories are stories of intimacy and private affairs, and yet many of them take the reader into public settings. We see the woman in "A quick one," trying to manage her nerves, struggling not to burst into a panic attack because she is about to break up with her boyfriend. In "To the cinema," the public theater raises religious questions in the narrator's mind, confusing the private issue of religious belief with the public shape of the theater. The imagery of public is suggesting that society is just a bunch of humans all dealing with intense personal issues, nearby one another.
School and innocence
The imagery of school is used as a concrete portrait of life's innocence. For this imagery to be seen in its full shape, look at the story "College;" in that story, we see both sides of the coin. Gillian, the representative of innocence, understood college in one way, through the lens of innocence, but now she has died, and her sister sees because of that loss the true value of school. She doesn't care about money or employment or the American Dream, or a degree—she leaves, hitch-hiking into the chaotic world without even saying goodbye. The widower in "A story of folding," remembers meeting his wife in school. The aging man in "The unthinkable," meets a little school girl who reminds him of life's strangeness. The portrait of innocence lost is shown as intimately connected with school.