So you have thousands of pictures and keep adding up on your storage device either in Internal hard disk or external backup drives in Terra byte ( that is 1,024,000,000,000 or 1024 Giga bytes. Please correct me techies out there).
Case 1: Accidental dropped the enclosure drive and when plugged to the USB port of any computer, it can’t be read. Hard disk is dead.
Case 2: Save it on some internet storage and amazingly, you can not access it anymore.
Case 3: Saved it long ago on CD/DVD recordable disk when you try to open it it warned of CRC or cyclic redundancy check and can not read the media.
Case 4: You lost or stolen your storage device or computer.
For case 1 fix, unless you worked with NASA or the CIA, they could easily retrieve the data. 2003 when the Space Shuttle Columbia crashed from reentry but in 2008 the data was retrieve. Case 2, 3 and 4 I have no idea yet. With CRC, many DIY tips are offered like scrub toothpaste until the scratches are out.
How long data last in electronic storage? 30 to 50 Years.
How about data in paper? Hundreds to Thousands of years. You could always refer to old manuscripts in museums to prove my point. Some old text of the Gospel in the Bible are dated between 3 to 8 AD. Other scrolls are BC timeline. If you want those precious pictures to last that longs, print it on paper.
If you want until eternity, carve it on stone. Metals is also fine.
And if you like paper, plant trees too.