I just printed out the blow up of the bottle (so I could check with images of bottle labels) and I am sure it is a bottle with two labels on it.
What I thought was a bottle stopper is actually the lady's ear lobe and a small black shadow on the coat of the man behind so making it look as if something is stuck in the bottle

.
One label is at the top and is a collar label (like on a Heinz sauce bottle although the larger label is the wrong shape to be that) and the screw top has been removed. I am not sure it is a beer bottle as the shape seems a bit wrong.
So my guess if it is a waitress holding the bottle could it be either a sauce or relish bottle?
The lady looks slightly embaressed to be in the photo or perhaps because she has to hold the bottle

Still trying to figure out why the bottle's there. Unless it's a product from the factory behind but if so why can we not see the label more clearly.
Jean