The OED online tells me that "snapshot" (as a noun) goes back to the early 1800s in print and referred then to a more-or-less un-aimed shot using a gun. However, the word took on its photographic meaning not long thereafter, whereas I'd expected this connotation (now a denotation) to come from the early 20th century:
[1860 HERSCHEL in Photogr. News 11 May 13 The possibility of taking a photograph, as it were by a snap-shot{em}of securing a picture in a tenth of a second of time.]
(Quoted from the OED online)
Snapshot
By any means, capture an image,
mark an instant's interplay between
light and facial shape. Shuffle the image
off into memorabilia, through which
someone may sort or rummage some day
not soon. Whoever it is will wonder
whose image was captured back then,
back here, where at the gathering
we think we know who's here, what
they're wearing, what they show. So
yes, of course, take an image from
the flow, stabilize it in one of
the ways we know. Store it, for it
may be of interest one day, could be.
Copyright 2009 Hans Ostrom