Digging
As readers learn more about the secrets of the Hemmings family, digging imagery becomes more common. Freak, one of the members of the Hemmings family, is obsessed with digging. As he digs, Freak uncovers more about his family and unearths long-buried, insidious secrets that no one, especially the family's matriarch and patriarch, wanted to come out.
Racism
There is powerful racist imagery throughout the novel, and it is directed mostly toward Malcolm, the adopted Black child who has been brought into the family. As more secrets are unearthed and as Malcolm gets treated progressively worse, racist imagery becomes more common, showing its harmful effects.
The empty pool
The imagery of the empty, dilapidated pool at the mansion where The Freak lives underscores the desolation of the Hemmings family and their soul. Furthermore, it is symbolic of the family's moral and emotional bankruptcy. To that end, as the family's moral and emotional bankruptcy becomes more evident, the empty pool is brought up more.
The dead bird
At one point, a dead bird hits a window, killing itself. Not only is this a metaphor for the characters' personal struggles, but it is stark imagery that reminds readers of the family's violent past (and, to a lesser extent, present).