I would be a little cautious about this. First of all, if the phone was stolen in June they might not be the ones that actually took the phone. Second, since it is a blackberry there is a lot of information that could be stored on it leading him to you (i.e. your address/contacts etc.). Definitely contact the police since it is stolen property but I wouldn’t jump to conclusions and cause the person to feel threatened. You did say that these were the latest pictures so if he has had the phone all along and you know that he is the one that stole your phone … GET HIM!!!
And do tell us how this all turns out. We all love a happy ending. Happy hunting!