The still is pretty irrelevant. What matters is the video the jury saw.
Quite.
None of us have seen the video so it is impossible to determine exactly what has happened.
The facts are thus:
1) The guard gave the ready to start signal when the person was leaning against the train. It's likely that because of the train's controls, McGee did not, and could not see the person then approach the train and touch or lean on the side.
2) The guard, having sent the ready to start signal, leant out of the train and then clearly saw the person touching or leaning against his train. The appropriate action in this circumstance - and what the guard had a duty of care to do - was to send a further "one on the buzzer" to stop the train from departing. That's all he had to do.
3) McGee instead allowed the train to depart having shouted and gestured at the person to move away. He continued to allow the train to depart even as she was stumbling (a stumbling which took place over several seconds), and only stopped the train once she was actually underneath it, sustaining fatal injuries.
This is why McGee is in prison.
I do, however, disagree entirely with the length of sentence imposed - but then that is the nature of a justice system that applies to 55 million people. We probably all have our own idea of what is an appropriate sentence in these circumstances would be, and I expect that if we disclosed them they would vary widely.
What is worrying is that the RAIB report still leaves many questions unanswered. I've heard interpretations of the timeline of events that suggest that the deceased stumbled away, then towards the train, as if this was done deliberately. The fact is, the deceased was very drunk, was in contact with the train and I am not altogether surprised that once the train began to move she stumbled (I imagine), like a newborn giraffe to her death.
It would be infinitely preferable if the CCTV video was released to the industry so these questions can be resolved once and for all.