SDrescan is small and easy to use:
https://play.google.com/store/apps/details?id=com.bero.sdrescan

If you happen to have a custom rom with dev tools installed, use that:
Launch "Dev Tools" => Media Provider => Scan SDcard

Both ways hide the manual steps from you and you can't delete stuff by mistake this way.

SDrescan is small and easy to use.

If you happen to have a custom ROM with dev tools installed, use that:
Launch "Dev Tools" => Media Provider => Scan SDcard

Both ways hide the manual steps from you and you can't delete stuff by mistake this way.