Above: A still from a video purporting to evidence the murder of an American citizen by the Islamist organization known as ISIS or ISIL, 2014. Credit: Public domain.
The defining quality of a jpeg photo published on the World Wide Web is that of its being indeterminable. It's veracity and authenticity is "incapable of being decided or settled" (OED). It may be authentic, or not. It cannot be said for certain. Indeterminable is an apposite term in that it also implies or introduces interminable too: such debates are indeed "boundless, endless" (OED). A photo on the World Wide Web is indeterminable but this does not render it as being beyond critique, far from it: it is immediately subject to critique. With always its provenence ("the fact of coming from some particular source or quarter; origin, derivation" OED) as the initial factor to be considered.
(1 February 2018)