Assassination photos - photographers' opinions, please

[Matilda]

I have just read this interesting website that discusses whether the Zapruder film of the assassination of President Kennedy might have been tampered with to bolster the one gunman theory. It's certainly very odd that the film was kept from the public so long; I've often wondered about that, but couldn't come up with a reason for it.

It goes into considerable technical detail - I understand what they're saying, but I don't have the technical knowledge to know whether the reasoning is valid. If it is correct, it's an extremely clever piece of deduction and makes an excellent case for conspiracy.

But does it stand up? I hope a few of you will take a careful look at what the site says and offer your opinions.

http://assassinationscience.com/johncostella/jfk/intro/index.html