Bob (Abell, that is),
Photos have been able to lie for (almost) as long as they've existed! A classic example is this one **LINK** which, after they had fallen out of grace in the Stalin era, was retouched to remove Trotsky and Kamenev so that they should not be shown as having been in Lenin's presence.
On a rather less sinister note, another example would be my father, who had a birthmark on the top of his lip; nothing disfiguring or anything, but a clearly visible birthmark; in my parents' studio-made wedding photo from 1965 it has been very expertly retouched away, as was, I think, common practice in those days …
Bob (Wilson, that is),
The "but everyone knows that" fallacy of thought is a very common one, and far from limited to computer programmers (although they are indeed heavy sinners on that account). One of my pet peeves here in Belgium is the seemingly innate inablity of local authorities when sign-posting their roads and local facilities to even for a moment try to enter into the mind of someone who has not spent his or her entire life in their village, and might not know that what used to be Jones Hill is now Smith Valley or whatever.
My wife and I once went to see Flemish stand-up comedian Bert Kruismans, who did a very nice riff on this theme: his line of work, he said, takes him to Parish Halls and Cultural Centres all over the place. On leaving the motorway on his way to a gig, he would find both village and hall well signposted, a bit further they would still be prperly signposted, same again yet further, but as soon as he got within about a mile or two of his goal, all signs would disappear, because "if you don't know where you're going, what the **** are you doing here anyway"! 
Mattias
Edited By Banjoman on 10/02/2017 09:11:44
Edited By Banjoman on 10/02/2017 09:12:25