At the moment with Android there’s no built-in method to refresh the media library. To do this after adding music, videos or pictures to your Android device, simply use the application SDrescan. You’ll find this on the Android Market and it’s completely free.

What SDrescan does is rescans for new or removed media files. Simple but effective.

Google play: https://play.google.com/store/apps/details?id=com.bero.sdrescan