The <PhotoOverlay> element allows you to geographically locate a photograph on the Earth and to specify viewing parameters for this PhotoOverlay. The PhotoOverlay can be a simple 2D rectangle, a partial or full cylinder, or a sphere (for spherical panoramas). The overlay is placed at the specified location and oriented toward the viewpoint.
E. Wällnitz, and T. Weise. Proceedings of World Conference on Educational Multimedia, Hypermedia and Telecommunications (EDMEDIA'05), page 4700--4704. Association for the Advancement of Computing in Education (AACE): Chesapeake, VA, USA, (2005)