Duplicates
At the end of the film we see rows of drowned duplicates of Angier as the theater burns down. The imagery reveals Angier's willingness to drown himself every night for a trick - a connection to his grief and blaming himself for his wife's death. It also shows us the reality of death that the two men have created in their rivalry.
Death or Magic
We see Cutter perform a disappearing canary trick for Jess. He then makes it reappear. Later we learn that the first canary was killed, smashed into the collapsing cage underneath the sheet in order to create the trick. The imagery connects the idea that magic, while engaging and delightful, can also hold with it a great price once must be willing to pay.
Masks
Angier visits Borden in prison with Borden's daughter Jess. Angier pretends to be a Lord who wants to help Borden by raising Jess, but only if Borden gives him his magic tricks. Borden does and the man rips them up and reveals himself. The imagery shows the cold-hearted nature of the magician's rivalry. That they will stop at nothing to destroy one another. That the magic means nothing, only revenge.
Lighting
We watch as Angier steps into Tesla's transportation/duplication machine on-stage during his performance. The machine lights up with electrical currents that can be seen and that look like lighting on the stage. The imagery shows the spectacle that both terrifies and attracts audiences to pay top dollar for a magic show. But the dead bodies beneath the "show" reveal that they are only seeing what the magician wants them to.
