The Special menu lets you preview audio files so that you can quickly browse and find songs on your computer. You can play AIFF, MPEG 4, MP4, MP3 files, and any other audio file that can be opened by QuickTime.
Open the Application Wizard pane in System Preferences and click Menus.
Click the Customize Menus button. In the dialog that appears, click Special.
Click the Customize Previews button. In the Previews panel:
Deselect the "Play music" checkbox if you do not want the Special menu to play audio files. Alternatively, you can disable previews for specific types of audio files.
Deselect the "Frame previews" checkbox if you do not want to display album covers in a frame.
Drag the "iTunes artwork" slider to adjust the size of album covers.
If the Special menu does not play songs despite the "Play music" checkbox in the Previews panel is selected, you may have disabled previews. To re-enable them, click the Customize Menus button in the Menus pane of the Application Wizard preferences, click Special, and select the "Show previews" checkbox.