Thanks, I got the frames from the photo gallery link.
I don't see anything that proves an earlier shot. Kennedy's hand is high as he is waving to passers by. He holds that last high wave (nothing unusual about that) and appears to turn to Jackie. They could have been simply sharing a laugh about what they had seen or heard, to the right of the limo - "We love you Jackie!" - "Ha ha! D'ya hear that Jackie?".
The first visual sign of an impact is just as they emerge from the sign.
Griffith is stuck in the last the Century and hasn't grasped the advancements of stabilization, and anyway, I wouldn't trust anything that Griffith claims he sees in the Zapruder Film because he is on record claiming that huge sections of the entire Film have been Faked, like his absurd analysis that Brehm's son shows movement that is impossible, and that's only the start of his long list of amateur observations!!
The Zapruder Film in this stabilized GIF from frame Z182 through to Z247 clearly shows nothing unusual about Kennedy waving as he disappears behind the Stemmons Freeway sign, but when he emerges both elbows suddenly and quite dramatically raise and at the same time Connally is violently reacting, to deny this simultaneous reaction to both Men being struck by CE399, is insane. And addressing Griffith's so called "Rosetta Stone" LOL, before they reach the sign, the entire occupants of the Limo are aware of the first gunshot, hence Jackie checking out the welfare of her husband but when JFK is actually hit, this is the point in time that Jackie reaches out to JFK and places her reassuring hand on his obviously just raised elbow.
An even slower stabilized GIF of what is seen above.
Just before Kennedy goes behind the sign, his right Elbow can be seen casually resting on the side of the Limo and to claim that "It's pretty obvious that something odd is going on with his right elbow." is just another crazy ass amateur observation.
I picked out the two clearest Zapruder frames before the sign and the first Zapruder frame which partially obscures Kennedy's right elbow and I still can't see "something odd" with the movement of Kennedy's right elbow or arm!
Btw here's a stabilized real time view of Brehm's son and the "impossible' movement! Hahahahahahaha!
JohnM