In poem "Snaps," how does Espaillat transform silence into observation of the gendered universe her poetry examines and explores?

The title of the poem, "Snaps," refers to two snapshots of a female: one when she is a little girl and one taken when she is 17. Photos are silent: they cannot speak in literal words. The figure in both poems is rendered even more silent by being a carefully posed object in a photograph. In both photos, she looks the way other people want her to look, and in both her personality is flattened. Both photos, thus, become a metaphor for the way a woman in patriarchal society is not allowed a voice and is forced to conform to the image others want her to convey.
We see in stanza one an image of a girl who is "neatly dressed" in "white," a color typically associated with purity, and posed in "old light" that falls "flat" on a "featureless expanse of chest." Words like "old light," "flat" and "featureless" emphasize how the girl has been flattened out and made generic. She is depicted as the stereotype of any good little girl.
In the second stanza, her 17-year-old self is also forced to conform to "good girl" gender norms. "Ankles crossed," hands in lap, and "clean sweater" show without any words how she is pressed into what stanza three calls her "obedient pose." She also wears a "gold cross," showing she conforms to her family's religious faith. In stanza four, we learn "mama's touch" "bent" her "to the law," and "to sanctities of custom." In other words, the second photo also is supposed to convey that she is her mother's idea of a good girl: docile, constrained, religious, and clean.
But the silence of these "snaps" also communicates another side to this girl that is different from the perfect obedience, cleanliness and docility that gender traditionally assigns to a female. Behind her silence and outward conformity, the girl speaks another language to the narrator. In stanza five's "sharp tilt of the the jaw" and "small thrust of hip," the girl asserts her individualism and independence. The narrator ends by stating, in the final stanza, that although the silent snaps are supposed to convey that the girl will fulfill her gender role ("not cross this line," "[not] talk back," not take any risks, never deviate from being "good"), underneath the  surface they communicate that she will rebel: "flashing me a sign...yes, we would."