There are many answers to this question but I’ll stick with the one.
Around 1994 Lynn Picknett and Clive Prince wrote a book together called Turin Shroud: In Whose Image? the Truth Behind the Centuries-Long Conspiracy of Silence.
Whilst I disagree with their conclusions, they made a revelation that is pertinent to today’s researching of AltHist. The subject?
Photography.
To quote Picknett and Prince :
On a side note and meaning nothing – Lynn Picknett has been a Facebook friend of mine for years. She has even answered some of my annoying questions :o)