Then there is the issue of play back. Good luck trying to find a CD or DVD drive in 20 years.
Storage is very important for writeable disks. Cool and dark.
And the file formats will be different then too. Will JPEG or MPEG be readable in 20 to 30 years. Lets hope so.
Requires maintenance and update every few years. Check, back up, verify, check and update if necessary.
Ironically, low technology is the best way to go. Photographs.
You think you have storage problems, the Library of Congress tries to maintain original playback devices. So many file formats. So many codecs.
Yes, for archival photos, your cannot beat black & white silver based photographs.
I worked at a Marine base as a civilian computer programmer back in the '80s. One Marine told me about a demo he had seen. The highers ups were all abuzz over the new computers coming out and wanted to put all records on them.
He said that at the demo, the sergeant held up a notebook with all the pertinent data about the company, then fired a .45 round through it. Then he went over to a CRT and did the same thing. "Now which one will still work?" he asked.