Little do you know about that story (one of many like it). Bill Simon wasn't the person who acquired and (supposedly) authenticated the photo. Candidates have campaign organizations that are supposed to cover such things. The man behind releasing that photo was Ed Rollins, Parsky's plant (and therefore a consequence of Rove's machinations). You are correct that it is Simon's final call to go with it or not. Still, if he had had decent support, it would have never happened.
AFTER the release of that photo, the campaign people (from Russo/Marsh) were posting the photo on FR to ask if it was doctored! (I was one of the people examining it to look for evidence of manipulation.) That's how incompetent they were about it. Simon bears ultimate responsibility, but IMO a GOP organization committed to getting him elected would have won the day. It wasn't.