snapshot n.

1550s, perhaps late 15c., "a quick, sudden bite or cut; an eager seizing," from snap (v.), or, if the earlier date, a noun from Dutch or Low German snappen "to snap," which are probably related to Middle Low German or Middle Dutch snavel "bill, beak," which Watkins traced to a hypothetical Germanic root *snu- forming words having to do with the nose, imitative of a sudden drawing of breath (see snout).

The sense of "quick movement" is recorded by 1630s; that of "something easily done" is 1877. The meaning "crispness, pithiness" is from 1865, American English (Scottish English had it by 1790 in an adjectival sense of "sharp, smart"). The meaning "brief or sudden spell" of weather (usually cold) is from 1740. The meaning "catch or fastener (of a purse, etc.) that closes with a snapping sound" is from 1815.

The card game name is attested from 1881, from a call used in the game. Meaning "a photographic snap-shot" is from 1894. U.S. football sense is from 1912, earlier it was snap-back (1880), which also was the name for the offensive center position. Slang snaps "handcuffs" is by 1895. Snap, Crackle and Pop, cartoon characters associated with Kellogg breakfast cereal Rice Krispies, are from 1940.

As an adjective (1790) commonly used to indicate instantaneous action, as in snap judgment (1841).

Middle English shot "a missile, arrow, dart" (senses now archaic or obsolete); "a swift movement, a gushing out," from Old English scot, sceot "a shot, a shooting, an act of shooting; that which is discharged in shooting, what is shot forth; darting, rapid motion."

This is from Proto-Germanic *skutan (source also of Old Norse skutr, Old Frisian skete, Middle Dutch scote, German Schuß "a shot"), from PIE root *skeud- "to shoot, chase, throw." The Old English noun is related to sceotan "to shoot." The meaning "discharge of a bow, missile," also is from related Old English gesceot.

The noun was extended to other projectiles (balls, bullets) by mid-15c. Especially "lead in small pellets, a small ball or pellet," a number of which are combined in one charge, which is attested by 1770 (shortened from earlier small shot, 1727).

The general sense of "an attempt to hit with a projectile" is by 1650s. Extended to sports (hockey, basketball, etc.) by 1772, originally in curling. It is attested by early 15c. as "range or distance of a missile in flight," hence "range" in general (c. 1600), as in earshot. 

Another original meaning, "payment" (perhaps literally "money thrown down") is preserved in scot-free; also see scot (n.). The notion of "throwing down" might have led to the meaning "a drink," first attested 1670s; the more precise meaning "small drink of straight liquor" is by 1928.

The sense of "hypodermic injection" is attested from 1904; the figurative phrase shot in the arm "stimulant" is by 1922. The broad meaning "a try, an attempt" is by 1756; the sense of "remark meant to wound" is by 1841. The meaning "an expert in shooting with a firearm" is from 1780; the sense of "a rocket flight" is by 1934. The camera-view sense is by 1958.

To call the shots "control events, make decisions" is American English, 1922, perhaps from sport shooting. Shot in the dark "uninformed guess, random attempt" is by 1885. Big shot "important person" is from 1861. 

By the rude bridge that arched the flood,

   Their flag to April’s breeze unfurled,

Here once the embattled farmers stood

   And fired the shot heard round the world.

[Emerson, from "Concord Hymn"]