The image is not a depiction of Heruka. It is just a skeleton. A Heruka mask is quite different. The accompanying dance that goes with this costuming can be seen in the background of this image . The monks from Drepung Loseling along with other smaller monasteries perform these sacred dances for non-buddhist audiences though entertainment and cultureal events.
I think it is very unusual that there is a heart on the center of the skeleton's sternum. The heart is not a Tibetan symbol, has no meaning attached to it in Tibetan or buddhist culture and I have never seen one on the many skeleton costumes I have seen. It almost looks like it had been added when the tinting was done.