Online bf / dating? I take it that you have not meet him face to face and if he sent you a picture it more than likely not him. If you have never met him face to face you truly have no clue as to who he / it is. Have you ever spoken with your bf?
Your 'online bf' could be a kid, young man, older man, pervert, criminal, married, murderer or an enemy of yours tricking you to think that he is what he is, etc.
There is this thing that we all are born with: fear. If you gut tells you something is not right, then go with you gut. Don't second guess yourself or it could be too late.
Get out and meet people...if need be get finger prints and run a background check or a medical evaluation and leave the online bf / dating alone. It can only bring you misery.