While not quite equal to the dream yet, today’s cloud-based services let you download apps to your computers and mobile devices, and automatically sync to download, share, and sometimes edit your images and other files wherever you are.
Storage space is still limited: 100GB is the usual maximum, and this will generally cost you around $100 per year. Most services prefer one operating system or another; some play nicer with photographs than others; and some share more elegantly than others.
But most of these services offer about 5GB of storage for free, so there’s no reason that every photographer shouldn’t use one (or a few) of these cloud services to make sure your best high-resolution images are backed up and available, no matter what.