Originally Posted by Vinny
you can't tell who is taking who to school in still pics. They may be working on underneath techniques or shading a receiver to the inside or any number of things in practice sessions.
May I add that frankly, a person can't always tell what he is seeing watching live unless he knows the answer to these and similar questions either. In addition, people in the stands don't know what a coach told a specific player to work on.
For instance a DB may be told to change his footwork for better balance and not to worry so much about covering the receiver for a series of plays. The coach may see the DB improving his footwork and give him positive marks for practice, while the fans in the stands seeing the same player getting beat twice and draws a different conclusion - he was owned all morning yada yada yada.