Android: Make your picture gallery and other media apps load faster—and only the pictures and music you want—with a quick folder tweak to prevent certain directories from being scanned and loaded by those apps.
Your device folders and SD card can be overflowing with album art, icons, and other images or multimedia that you don't want as part of your gallery. If you'd like to make these apps skip irrelevant directories (such as a folder holding images saved from a kids' colouring app, shown here), all you need to do is create a blank ".nomedia" file in that directory.
To do so, use a file manager application (e.g., Linda File Manager) to copy a text file or an image to the directory. If you're using a text file, edit it to delete all the copy, then rename the file as ".nomedia" in the file manager. If you don't care about some of the images in a particular directory, you can also just rename one of the pictures.
This tip comes courtesy of the folks at AddictiveTips, who also offer other ways to prevent a directory from being scanned. Renaming a directory to start with a period, for example, will turn it into a hidden directory, and you can also use Android apps that disable media scanning as part of their features. Although AddictiveTips recommends trying Super Manager or StudioKUMA .nomedia manager for easy repeated use, if you prefer manual control over the process, you can simply create the .nomedia file yourself.
How To Prevent A Directory From Being Scanned By Android Gallery [Addictive Tips]