I did not like this idea but some people find such photographs interesting. Tesla and the photographer went to great lengths planning how they would produce these pictures using camera tricks. Other photographs show people with streamers flying out of their heads and such. They are always on some insulated platform to limit the actual currents passing through them. This is extraordinarily risky.
Some explanation is in order.
RF currents do not stimulate nerves. Therefore, one can have high frequency electric currents flowing through the body without feeling anything. There are at least three problems. First the electric currents can cause severe burns. Second once an arc path is set up between a person and a Tesla coil it is very easy for the energy in the primary circuit to short through to the output.