Like Skater and Dimitri, I agree that Aidan's toast.
I'm not going to wait until he gets home. If his friends are there, and he's embarrassed, too bad. If he's alone, and I smell smoke or alcohol, I'm going to quietly tell him to get in the car and we'll go home and deal with it. I'm going to check lest this is a "posed picture" for shock value. I very much doubt that's the case.
When we get home, we're going to have a serious talk about peer pressure, smoking at any age, underage drinking, the legal consequences thereof, and how very disappointed I am with him, both with respect to his behavior and his honesty about it.
I will then exercise the nuclear option in my parental arsenal, whatever that may be. I'm inclined towards having him go pick a switch.
That may well be the EASY part for him, since I'm going to be watching his activities closely, and monitoring his friends. If they're as bad as they seem, they are unlikely to want to continue hanging out with my newly reformed son. Forbidding contact generally is just an invitation to find a way to sneak it.