Spitting image or spit and image (sometimes reanalyzed as splitting image) stems from the metaphor of spitting out an exact likeness of oneself.
The metaphor appears as early as 1602 when Nicholas Breton writes in his book Wonders Worth Hearing, “twoo girles, [...] the one as like an Owle, the other as like an Urchin, as if they had beene spitte out of the mouthes of them.”
The noun spit appears two centuries later in the sense of an exact likeness of another person in Knapp and Baldwin’s 1825 Newgate Calendar, a compilation of various criminal biographies of the inmates of Newgate prison, “a daughter, [...] the very spit of the old captain.”
The phrase spit and fetch, the latter being a British slang term for an apparition or doppelganger, appears by 1859 in George Sala’s Gaslight and Daylight, “he would be the very spit and fetch of Queen Cleopatra.” And the English Dialect Dictionary has an 1866 citation for spit an’ pictor.
The EDD also includes a citation of spit and image from 1892 by songwriter and poet Richard Heslop, “he’s the varry spit an’ image on his fethor.”
The phrase spit and image has to be older though, as it is reanalyzed as spitting image by 1887, when it appears in A. C. Gordon’s “A Pinchtown Pauper” in the September 1887 issue of The Atlantic Monthly, “As purty as Mis Agnes, an de spittin image of her!” The phrase spitting picture is a bit earlier, with a gloss for spitten picter appearing in Dickenson’s 1878 Glossary of Words and Phrases Pertaining to the Dialect of Cumberland.
So in short, the metaphor to describe someone who looks like another as having been spit out by them appears by the opening years of the seventeenth century. By the early nineteenth century, the noun spit is used to denote someone who looks like another. Then by the mid nineteenth century phrases like spit and fetch and spit and picture appear. Finally, in the latter years of that century the phrase spit and image is reanalyzed as spitting image.
The idea that spitting image is a reanalysis of spirit and image is fallacious.
(Sources: Horn, Laurence. “Spitten Image: Etymythology and Fluid Dynamics.” American Speech, 79:1, Spring 2004, 33–58; Oxford English Dictionary, 2nd Edition, “spitting, adj.”; “spit, n.2”; “spit, v.2”; “spitten, adj.)
Copyright 1997-2015, by David Wilton