I'm asking you how you can tell that they are exactly the same.
Oh, well that's easy... I just put my assertion out there that the Muchmore/Zapruder headshots are "exactly the same" and dare anyone to disprove it.
If, after a week or so on this forum (with all its experts) no one can disprove my assertion, then it must be a fact.
But, in all seriousness, I'd say this is one of those cases where a lack of evidence is in fact evidence.
Either they are
different, or they are the
same.
Once again, what are the differences ?