Hi ADMout, this is in reply to your question 4 days ago: "I'm truly puzzled. I can see the point of stitching photos together to get a larger coherent image, but I just looked at a load of the synths here and, while many are great photos, I cannot see what's gained by splicing them in this haphazard way."
You need to look at the Point Clouds (Press 'P' on the keyboard). The photos are not haphazard and it's not just about making a bigger image. Photosynth reconstructs an entire 3-Dimensional universe from the 2-D photos.
For example, look at this synth of a human hand (Press 'P') -- and use the halo to rotate the scene:
The following synths are big and may take a few minutes to download to your PC:
Santa Barbara Courthouse: