The term vernacular photography is used in several related senses. Each is in one way or another meant to contrast with received notions of fine-art photography.[1][2] Vernacular photography is also distinct from both found photography and amateur photography. The term originated among academics and curators, but has moved into wider usage.
[T]he category of the vernacular is defined mostly by what it excludes: fine art.
If a photograph wasn't made for non-utiliarian, self-consciously expressive reasons that allow it to be designated 'art,' it devolves to this grab-bag left-over category designated 'vernacular.' Vernacular is thus defined not by what it is, but what it isn't.