Mid-2015 MacBook Pro: Photos have been corrupted(?)

I have this early-2015 MacBook Pro that holds valuable family photos. One day, however, the photos in a certain point of time have either a greyed out strip going through them, or the right side is a mirror image of the left. I restarted the computer, thinking it was a glitch: same thing. I thought the worst had happened and the drive was failing, so I checked S.M.A.R.T, but it said the drive was healthy. I'm confused on what to do, as these photos are very very valuable, not only to me, but to my entire family.