No, it doesn't, its a still image, he could be mistride and actually running faster than anyone else there. Secondly there is a old guy who "appears" to not be moving at all(ok its in the uncropped version of the pic, standing foreground to the right of where the pic is cropped). You have a bald guy standing still looking the other way, you have two people standing a bit further up than the bald guy looking down towards the explosion, you have the lady in the pink jacket on her power walk, you have the guy in the MIT top just walking across the street...etc, etc.
People see what they want to see, its a still, you can't guess his emotions, nor speed, nor motivation by watching, its a picture with a dozen people all reacting completely differently to the explosion, NOTHING makes what he's doing more suspicious than anyone else, nothing at all. Walking away is more suspicious than the people standing watching, or the people running towards the explosion or the ones running away from it, how, this is of course completely assuming he's walking and not running.
Exactly what I was going to say, a still photo is a snapshot in time, it can tell a lot but it also tells very little and can be completely misread. I see a lot of people in that photo who could be walking or just chatting and therefore suspicious by the assumptions made here. I also noted the position of his elbow which also indicates running rather than walking. His expression cannot be assessed from the photo either. So, overall, out of thousands of people present, no conclusion could be made about that person that distinguished him from anyone else in the photo.