2000.02.15 23:56 "Re: why are SGI TIFFs upside down on a PC or Mac", by Sam Leffler
The tools on the Octane write the images w/ an OpenGL-style origin and depend on the Orientation tag to get the image oriented properly. Photoshop probably ignores the tag and assumes the origin is in a different (e.g. Postscript) location.
Sam