I found this topic because my default Gallery app (I’m using an FP3+ on /e/OS 1.0) wouldn’t show my photos that (all of them) I had moved manually to the SD card. In fact the gallery wasn’t showing anything anymore. I might be to blame, I had deleted an odd file in the DCIM (not sure anymore whether on internal storage or SD card) folder earlier today.
I tried this and that (emptying gallery app cache and data, the same for media storage) to no avail. Gallery stayed all empty. So I resorted to installing and setting up (grant access to the DCIM folders on both the internal storage and the SD card) Simple Gallery. Simple Gallery displayed everything instantly.
The odd thing? Seconds later, when I had a look into the default Gallery app, it showed everything again, too It’s as if Simple Gallery settings affected the default Gallery as well. I even checked if the default Gallery was a fork of Simple Gallery, but it is not.
Anyway, I thought I’d mention this in case someone else runs into the problem in the future again.