The way it's supposed to work is, the mouse pointer allows the viewer to "pull" the image to left, right, up, and down. I'm using a 1999 Mac under OS 9.2.2, and it worked fine. :') Someone will come along with a helpful tip I'm sure.
Seti I's tomb was discovered by Giovanni Belzoni in 1817. I highly recommend the book "Belzoni's Travels" edited by Alberto Siliotti. Belzoni's drawings and journals of his travels in Egypt are very impressive. I also recommend "The Royal Tombs of Egypt" by Zahi Hawass. I got it for a Christmas gift and have only been able to leaf through it so far, but it contains a multitude of photographs and several centerfold photographs of the various tombs including Seti I.