In Windows you need to be admin level user to properly check. If the filesystem of SD card is FAT based of course. If not you need to add a proper driver for it first.
In Linux it’s much easier to mount and check the content as root (or superuser). At least for me ;).
What puzzles me is that you do see some pictures in the gallery. Can you please check that they are on SD card and not in the phone memory?
Backup is always highly recommended. Every memory eventually fails. I highly recommend that you do it ASAP on another card.
Good luck!


