Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

In the Zapruder film, JFK is smiling and waving at the crowd until he passes behind the sign. But, at the last second, he put his hand over his face? That's what it shows, but it's fake, and here's proof. 

So, in 207, he's got his hand in front of his face. But, in 225, he is in the process of raising his hand up to his face. It's 18 frames later, so exactly one second later. If his hand was in front of his face a second before, how could he bringing it up to his face a second later? And we have to assume that in the frames that preceded 225, his hand was lower than we see it in 225, that he had already started moving it up when he was behind the sign. So, how could he have his hand covering his face in 207? 

I think that he must have been showing a startled, panicked, distressed look on his face from being shot in the back which they covered up with that hand, starting at 196. And if you are wondering where the hand came from, it's probably paint. They didn't have Photoshop in those days, but they did a heck of a lot with paint. And they probably got the best in the world to do it.