This is multi layered but I’ll try to keep it brief
I had a couple of private pictures that I wanted to hide on my degoogled Fairphone 6
No matter where I’d put them the gallery app would pick them up and keep them visible, with no real way to hide them, I looked for an option to make a secret folder but to no avail
As I was looking for ways to hide the photos I realized there was a system folder that would not only be able to be hidden but it also was completely avoided by the gallery
So I made a foler in it and put the photos in there
That was well over four months ago, and no update until now has done anything to that folder
Today I updated and the folder is gone, or at least is unreachable, I had no backups of those photos and they seem to be completely
The system partition is fully overwritten by an update so I am sorry to say that anything there will be gone. There are complex symlinks within Android but if your folder seems overwritten then probably it is.
“Show hidden folders” will reveal folders named with leading dot as /.hidden.
However I think an image.jpg in the directory /.my_secret_store will still be found by Gallery. Not by Files app until you “Show hidden folders”.
If you rename your image as .my_image.jpg it will join other images in Trash, (hidden from Gallery, except Library) automatically named in /e/OS .trashed-image-name.jpg.
You might experiment with hiding images by rename extension, so my_image.jpg is renamed to my_image.kkk
Can you not find the folder now, my explanation was only for system partition which is not especially easy to write to anyway. Can you describe exactly where you put it?
Edit. Extra complication with FP6 you probably just has Android version Upgrade to a16. Possibly your image files survived previous updates but something different happened at Upgrade.
FYI A file named .nomedia in a folder tells to the media apps to ignore the whole folder and not to scan and not to index it for their galleries. Files are visible with file management apps. You may have just found such a system folder for your hidings. A user is free to create such empty file anywhere they wish.
A general feature of most gallery apps I’ve used is the ability to exclude certain folders from displaying images in the gallery, e.g. Music (to exclude album cover art).
Also, I beieve there are apps that can create a “secret” hidden folder in Android, if your goal is to hide some content from being seen by others.