This article explains what NOMEDIA files are and why you see them on your phone. We look at how to create and delete them to hide or show media files.
Android .nomedia File: How to Hide Media in Your Gallery and Music Player?
A file with the file extension .NOMEDIA is an Android No Media file. They are only seen on Android phones and tablets, or on devices that are connected to an Android device.
These special files never have a filename (they are always seen as .nomedia) and are used to tell other apps not to look for media files in the same folder where the NOMEDIA file is located.
For example, if there is a folder called Screenshots and there is a .NOMEDIA file in it, most apps that look for pictures/videos in there will understand not to read data from it. In other words, the folder will appear invisible.