Samsung Galaxy S4: How to Hide or Show Hidden Pictures or Videos in Gallery App in Android 4.4 Kitkat

A few days ago, my Samsung Galaxy S4 got update to Android 4.4.2 Kitkat via OTA. So far, it works well and doesn't cause any problem. I even like this Android version more than the previous one because this update brings some features I really like.

See also: New Options and Features in Android 4.4.2 Kitkat in the Samsung Galaxy S4 GT-I9500

Among the new features in Android 4.4 Kitkat, there's