I haven't read too much into the story, but here is a very quick rundown:
1) A photo of Michael Phelps smoking weed was leaked to the media.
2) The media is in a frenzy.
3) The media is saying that Michael Phelps may face charges.
There is only one item in this list that does NOT make sense.
1) Sure, Phelps should have known better, as an athlete and public figure, than to let someone (friend or foe) photograph him doing something like that.
2) Sure, the media is going to blow the story up to be bigger than it really is.
Why would Michael Phelps face charges for something that he is doing in a photo? It doesn't make sense. Instead of arguing my point I will give scenarios that follow the same logic as Phelps being brought up on charges:
1) A friend takes a photo of you playfully fighting another friend. Months later the police get a hold of this photo and arrest you for assault and battery.
2) The Chief of Police in Long Beach, California finally gets around to listening to Doggy Style and a warrant is issued for Snoop Dog's arrest.
3) A picture of you holding a bull horn in a public park somehow reaches the authorities and you are arrested and fined for disturbing the peace.
4) Robert DeNiro is arrested for murder because of his role in The Godfather II.
I think you get my point.