Assuming that this image will be released with a Commons-compatible license, sooner or later (maybe many years later), there will be a use case for increasing the Commons file size limit to 194GB: http://www.dpreview.com/articles/5817599570/astronomers-create-46-gigapixel-image-of-the-milky-way
Perhaps in a timeframe in the nearer future, could MediaViewer be tweaked to download and show only small portions at a time of large images and/or tiled sets of of images? I think this feature might get a lot of use from the moment of deployment.
Thanks!
Pine