If you have created a ".nomedia" file on your Samsung Galaxy S7 to exclude a folder from the Android media scanner, you may notice that pictures and videos are missing in the gallery.
The background is probably the fact that you created the nomedia file within an incorrect folder, or that you moved or copied it. But do not worry, because you can check if a .nomedia file is hidden in one of your picture folders.
To do this, you need the following app on your Samsung Galaxy S7: ES File Explorer
After downloading the app to your smartphone, open the app. In the upper left corner, tap the three-bar icon to display the File Explorer menu. Scroll down completely in this menu and activate the slider "Show Hidden Files".
Now you can search for the picture folder, which is no longer visible on your Samsung Galaxy S7 and possibly hidden by a nomedia file. If you found the .nomedia file, delete it so that you can make the picture folder visible again in the Android Gallery. Done!
You now know how to display a picture folder that was accidentally hidden by a nomedia file and is no longer visible in the gallery on the Samsung Galaxy S7.