Some people collect seashells or foreign stamps. Grace collects weird art school portraits from flea markets. "They were from the 1940s or ‘50s, of sour-looking models, captured by less than brilliant students. Together they formed a kind of gallery, of unlovely faces and rather judgmental observers" (13.36).
Good grief, even the artwork in Grace's apartment isn't likeable.
Her home decor choices emphasize how much of a facade her life truly is—she's going through the motions of being a good wife and mother, all while being watched by this artificial audience.
However, the portraits take on an entirely new significance just a few paragraphs later when Grace walks into the living room, lost in her memories:
Jonathan had been there that day...the paintings here, two studies of the same young man—from, undoubtedly, the same art school class, but very different painters...One version of the young man was so stiffly delineated that he bordered on cubism, is classic white button-down shirt and khaki pants rigidly arranged in a posture...that looked profoundly uncomfortable; the other rendered him so breathtakingly sensual that Grace assumed some highly mutual (though necessarily silent) flirtation had been ongoing throughout the class (13.45).
Hmmm, who else could possibly fit this description? Maybe the man literally sitting in front of these paintings in Grace's memories.
Korelitz is practically beating readers over the head with symbolism here, although Grace herself doesn't seem to pick up on it, instead ruminating on how crazy it is that two portraits of the same man ended up in the same thrift store. Oh, Grace. Your portraits are judging you for your inability to recognize the obvious.