some pix have disappeared after Galaxy S6 update

[Android Central Question]

in Gallery, some pix are greyed out. when i click on a photo (even if it's not greyed out in thumbnail screen), I get a black screen and scrolling left or right only gives me a black screen . i recently did a system update (Android 7). Videos seem not to be affected.
I did a Force Stop and cleared the cache and restarted. Nothing.
Galaxy S6

 

[B. Diddy]

Welcome to Android Central! First, try also clearing the data from the Gallery app, then open it again and give it a few seconds to rebuild the database. If the problem persists, then try wiping the system cache partition as well: https://support.t-mobile.com/docs/DOC-29236