One note about downloading the photos is that Photosynth stores all of the photos' original metadata (camera information, photographer name if provided, etc.) in facebook-sized versions of your photos called thumb.jpg, but all of the image tiles for the original resolution of the photos are completely without any metadata (because saving the same metadata tags in hundreds of tiles for each photo doesn't make sense).
The only reason I mention this is that in order for Henri's TileDownloader to put the original metadata in the full sized photos, you'll need to run step 1 of downloading the synth point cloud and camera parameters and *choose to download the thumbs*.
Then after that is complete, run the later step of downloading the HD versions of the photos and the downloader will automatically read the metadata from the thumbs and write it the full resolution photos. They won't be perfectly identical to what you uploaded, but will be as close as they can be.