I recommended in the February Suggestion thread that we should sell as an accessory Certificates of authenticity as i had this kind of thing in mind, the amount of digital prints photography/digital art selling is growing yearly.
A certificate of authenticity would offer the buyer proof of purchase, artist name, print dimensions, paper used, sale number, and price paid. I say that information would be really useful when the print came up for resale.
There are some amazing digital artists/print designers out there and it is obvious some artists work is more desirable than others.
When that artist passes away, like art the value of that digital artists work will increase in value, investing in digital art has a future, a certificate of authenticity definitely has a role to protect and increase the original value.