Can you elaborate on this a bit more as it seems a bit dubious...
You are saying you snapped this picture using the remote app you are using to monitor?
It's clearly not the person who stole the phone, so what was he doing? Holding it up to show this guy or take a picture of him himself and you just took the photo during monitoring?
Although somebody might know this guy, you want to be very careful how you tread with an internet campaign to find your phone, especially if you go posting on 4Chan. You may well be looking at a guy here who is totally innocent and could end up defaming him.
It did cross my mind that he could be innocent, hence the 'this man knows who stole my phone'. The 4chan was semi joking and more in relation to the phone number of the sim card that was inserted into the phone very shortly after it was stolen so I can be fairly sure that does belong to the thief! I was a bit frustrated at the time so the thought of loads of internet random people pestering was a little amusing!
If I don't see it online again for a few days I'll probably just call him at some point and tell him I'd like my phone back!