Cymbeline: Metaphor Analysis

Imagery
Buying, selling and worth
Images of buying, selling and worth are prominent. Belarius values his life in exile because it has enabled him to pay "more pious debts to heaven" than he did in his life at court. The cynical Iachimo implies (Act 1, scene 5, line 15) that as a poor man, Posthumus's worth is only borrowed from the King's daughter, that he is "weighed rather by her value than his own." In the same scene, Posthumus and Iachimo discuss in detail what Imogen, and Posthumus's diamond, are worth. Iachimo also tries to set Imogen against Posthumus by accusing Posthumus of going whoring on her money (Act 1, scene 7).
Gold, the basis for currency as well as a potent symbol of incorruptible worth (gold does not tarnish) is a related theme. Cymbeline (Act 1, scene 2, line 73) accuses Imogen of making his throne "a seat for baseness," a reference to base metals of low worth; Imogen replies that she has added "lustre" to it (line 74), a reference to precious metal such as gold.
The value of gold was determined by weight. The cynical Iachimo implies (Act 1, scene 5, line 15) that Posthumus's reputed worth is only borrowed from Imogen, the King's daughter, and that he is "weighed rather by her value than his own". Cloten hopes to bribe Imogen's ladies with gold (Act 2, scene 3). Cymbeline is expected to buy peace by paying a tribute. Cloten says (Act 3, scene 5, line 75) that Imogen "outsells" all other women, whereas Posthumus's base "weights" (line 89)-pieces of cheap metal-are worthless.
Nature: flowers, trees, animals and birds
The animal and bird imagery that runs through the play has two main functions: first, to establish the theme of "great creating nature"; and second, to establish a hierarchy from grossest to most refined, into which various characters and their actions fit.
Many characters are likened to birds. Belarius imagines that the gods see him, from heaven, as a crow (Act 3, scene 3, line 12). Arviragus and Guiderius are "the poor unfledg'd," baby birds who have never flown the nest (Act 3, scene 3, lines 26-7). Posthumus's alleged seductress is "some jay of Italy" (Act 3, scene 4, line 49). Imogen likens Cloten to a "puttock" or kite (Act 1, scene 2, line 71), a much less noble bird of prey than the eagle, to which she likens Posthumus (Act 1, scene 2, lines 70-1). The Roman army is also symbolized, in the Soothsayer's predictions, as the Imperial eagle. In Shakespeare's time, humans and the animals and plants were seen as occupying different ranks on a hierarchy from lowest to highest. The different members of the hawk family were all assigned gradations in a hierarchy of their own and people were forbidden by law to hawk with a bird assigned to a higher rank than they occupied. The eagle was considered the noblest bird of prey and only an Emperor was allowed to hunt with one.
In Act 1, scene 7, Iachimo calls Imogen "alone th' Arabian bird," a reference to the legendary Phoenix. The Phoenix is said to have risen from its own ashes, out of the fire which burned at the top of the sacred Persea Tree at Heliopolis. It was a symbol of the rising sun and of the dead Sun-god, Osiris, from whom it sprang, and to whom it was sacred. The image foreshadows Imogen's later rebirth from her seeming death, and also conveys her uniqueness.
Iachimo's speech is laden with animal imagery of the less refined sort, as befits his gross nature (Act 1, scene 7, lines 39-50). He invokes apes, which, he says, would discriminate better than Posthumus does between Imogen and the imaginary "slut." He likens Posthumus to a predator which devours the lamb (Imogen) but, still hungry, wants to feed on "garbage."
Arviragus's use of animal imagery gives a different flavour. He says of his adoptive family's life in the Welsh hills: "We are beastly: subtle as the fox for prey, / Like warlike as the wolf for what we eat" (Act 3, scene 3, lines 40-1); he goes on to liken them to caged birds (line 43). His language emphasizes the restrictiveness and savage (in the sense of wild) quality of their existence.
A more refined set of natural images, those of flowers, is seen in Arviragus's speech in Act 4, scene 2, lines 218-229. Arviragus describes the flowers he will strew upon Imogen's grave, a symbol of life amidst death. Cymbeline is likened to a cedar tree, and his lost sons to the lopped branches of this tree (Act 5, scene 5, line 454 and 439).
Poison and disease
In Act 1, scene 2, line 59, the King accuses Posthumus of being "poison to my blood." Iachimo uses images of rot, decay, disease and poison to excite disgust at Posthumus's supposed life of whoring: "Such boil'd stuff / As well might poison poison!" (Act 1, scene 7, line 126). There is irony in the use of these images, as the real poison lies not in Posthumus's nature or in his mode of living; it lies in the poison slanders that Iachimo drops into Posthumus's ear, and in the very real poisons that the Queen intends to use on those who stand in the way of her ambitions.