I discovered something, maybe someone is interested, so I'll write it briefly.
If you take a picture with the camera (whatever else, right) and then look at it in the gallery, it is cached as a preview. If you delete it, it is gone in the gallery and if you then empty the trash, it is not saved anywhere (is temporarily saved in /storage/emulated/0/MIUI/Gallery/cloud/.trahsbin). Nothing new so far.
But: if you look under /storage/emulated/0/Android/data/com.miui.gallery/gallery_disk_cache/full_size or small_size, you can still see the smaller pictures, so to speak the small preview pictures in the gallery (you can rename the .0 to .jpg). Even the oldest ones that have been made and deleted long time ago were there, just smaller (less than 1MB), but they are there and take up memory. Even a restart does not delete them. I don't know if there is any limit and if it will not be erased at some point. Otherwise it is just a kind of second backup or the memory will run out at some point in the case of frequent photographers or video takers. The security tool did not remove them when you tried to use the cleaner tool. At least in my case it didn't.
If you take a picture with the camera (whatever else, right) and then look at it in the gallery, it is cached as a preview. If you delete it, it is gone in the gallery and if you then empty the trash, it is not saved anywhere (is temporarily saved in /storage/emulated/0/MIUI/Gallery/cloud/.trahsbin). Nothing new so far.
But: if you look under /storage/emulated/0/Android/data/com.miui.gallery/gallery_disk_cache/full_size or small_size, you can still see the smaller pictures, so to speak the small preview pictures in the gallery (you can rename the .0 to .jpg). Even the oldest ones that have been made and deleted long time ago were there, just smaller (less than 1MB), but they are there and take up memory. Even a restart does not delete them. I don't know if there is any limit and if it will not be erased at some point. Otherwise it is just a kind of second backup or the memory will run out at some point in the case of frequent photographers or video takers. The security tool did not remove them when you tried to use the cleaner tool. At least in my case it didn't.