That is from John Armstrong's bio page of Jack Ruby, and it is probably the most detailed bio of Jack Ruby that you are going to find on the web.
But, let's hone in on this fact that Ruby was 5'8 1/2". That was just a half inch shorter than Oswald, but it was a lot taller than the Garage Shooter.
That guy is short. He is no 5'8 1/2". We estimate his height to be 5'6". And the same applies to him here: