The Media Browser provides access to all the media files in your iPhoto library, your iTunes library, your Aperture library, and your Movies folder. You can drag an item from the Media Browser to a slide or to an image well in an inspector.
If you don’t use iPhoto or Aperture to store your photos, or iTunes for your music, or if you don’t keep your movies in the Movies folder, you can add other folders to the Media Browser so that you can access their multimedia contents in the same way.
Click Media in the toolbar, or choose View > Show Media Browser.
To add a folder containing audio files, click Audio in the Media Browser, and then drag the folder you want from the Finder to the Media Browser.
To add a folder containing photos, click Photos in the Media Browser, and then drag the folder you want from the Finder to the Media Browser.
To add a folder containing movies, click Movies in the Media Browser, and then drag the folder you want from the Finder to the Media Browser.