Infinite perfect copyability has always made it a challenge for photographers to make it in the fine art world, because the fine art world is about selling unique items, and a print (analog or digital it doesn’t matter–or at least it didn’t used to matter, this idea may give digital an advantage) is by its very nature one of potentially many.
I’ve seen various photographers adopt various strategies–the most common I see is signing and numbering a limited edition of prints. This is not a bad solution, but, it effectively limits the possible high end. A photographer makes an edition of x number at $x.xx per print and solves for a reasonable value after already recognizing that the value is being artificially reduced by a market that views “copies” as lessening a value. So a search for a sweetspot of pricing happens. The more I make the less each is worth, but, the beginning value is too low because even the theoretical possibility of more is enough to make the item less “rare”.
But what if an SD card were manufactured that were write-only, tamper-proof (well, that would show visible evidence of tampering if it were to occur), and would erase itself after one unlocking.
Now a photographer could offer for sale the SD card and its original contents. The images could be previewed on a digital frame or other device, but to make a copy of any image or all images would require activation of the key that would erase the contents after copying. The buyer would own his copy of the data, along with the ability to make more copies or prints as desired. It breaks the unique-object chain after the first buyer, so it doesn’t totally solve the problem, but it does give a buyer/collector something of far more value than a print of an image the photographer retains.