[Jolly Well]

As long as you were photographed in a public place - on the street, in a park, in a store, at a restaurant - where anyone can see you, someone can photograph you and publish it for editorial usage. It doesn't matter if you're a regular Joe or a celebrity; there's no reasonable expectation to privacy if you're walking around in public.

The photographer actually owns the copyright of the photograph, and as odd as it seems; you wouldn't be able to use that particular image of yourself without his consent.

It gets tricky if he tries to sell your image for profit. Then he would most likely need a model release.

If he worked for the festival and took the photo on their property, then he most likely doesn't need your permission; but even that can be iffy. Check the contract you signed and see if you may have unknowingly signed a waiver.

Without knowing who the photographer, you may have a difficult time making any progress if it's your intent to have the photo removed.

How exactly are they using your image? That may make a difference, but it sounds like it is going to fall under editorial use rather than commercial.