For what it's worth, they're usually also writing a DICOM player to the disk so the entire study can be viewed and manipulated as if it was taken on a machine your provider has access to. It isn't as simple as something like a folder of JPEGs. The point is to make it as standard as possible so that any provider can view, adjust, and manipulate the study. Most electronic health record software has this built in, and your doctor probably can already see it if they have compatible health record systems. But the absolute simplest and most universal method for sharing these studies is on a disc. It's essentially guaranteed to work for any medical provider right now with no effort on their end. Put the disc in and go. All the other ways are less reliable unless you know certain details about who will be viewing it.  

 These systems weren't designed for patients, but it's worth noting that you can pop the disc in yourself and have all the same abilities if you want. I guess they could create virtual disc files and somehow transmit them but the files are large and it again isn't as standard or simple as just opening and closing a disc tray. You'd need to know how to mount a virtual disc, etc.