This image is reputed to be Fedurici (English Tenor Frederick Bake) who haunts the Princess Theater and was killed after having a heart attack and falling through a trap door on stage. The image was captured during filming of The Devil in the evening Dress. It was about Federici, the ghostly opera singer who reportedly haunts the Princess Theatre. The documentary was done by George Miller and Byron Kennedy who would later go on to produce Mad Max. The picture was taken as a souvienier by an extra on the film who only noticed the figure later, a snap taken seconds beforehand has no image visible. Full story at here