It doesn't. It's a still photo, we've seen in the past (most notably in the Philly/AOS affair) that they can give a very misleading impression. That's specifically why they're inadmissible as evidence in appeals etc. You can't prove to me or anyone else that Maguire's hurley isn't a inch away from Blanchfield's arm in that shot.
Incidentally while the rule allows the ref to send off a player regardless of whether he struck or attempted to strike, he has to specifically say which it was in his report if the punishment is to stick. That's how Mayo were able to use the seemingly bizarre defence that Lee Keegan had only attempted to kick Johnny Buckley rather than kicking him with minimal force to get him off that time, even though both are sending off offences. If the ref decides to say that Maguire struck Blanchfield, I think we'd stand every chance of getting him off as the video evidence doesn't prove he did IMO.
Agreed on that at least.