Facing issues in gallery I'm using one plus 6 and I'm facing issues with my gallery. If I save pictures from Facebook, Snapchat or any other app it doesn't show up in gallery. Only screenshots and camera pictures are showing
I've tried almost everything clearing cache, uninstalling installing apps, force stop, .nomedia (It wasn't there )
The possible reasons are :


The app is built in a way that it only reads media files from some directories like DCIM>CAMERA, Pictures>Screenshots, main directory, Internal>Videos etc. It will not read the media files from the folder named with the application names like WhatsApp, Facebook, Snapchat(some popular applications).
The Apps like Facebook, Snapchat will change the encoding of the image by reducing the size(still it may be in JPEG format). This encoding can't be read by the gallery apps.
Hidden files are also can't be detected by some gallery apps(saved media from popular apps are not hidden but all thumbnails are hidden).
Some apps give file names as a random character without file type like
dfasvssvd56 rather than dfasvssvd56.JPEG but may or may not be encoded differently. This will result in not detecting the image.