Although it appears, disturbingly, that the boy's foot is on fire, it is, in fact, not. This is the bucket, just after someone kicked it, in an attempt to put the fire out. It didn't. Miraculously, no photographers, fire painters or small children were injured on the night.
Particularly when the "father" of the light painting troop was throwing flaming balls of fire to his young children to "catch". Isn't that called child abuse? :)