Shortening the Audio Clip
Hover the mouse over the end of the music clip until it becomes a two-headed arrow. Drag the end of the music clip to the left to line up with the last picture.
Note - In this instance, I will have to drag the end of the music clip several times to reach the beginning of the movie due to its size. It is easier to do this if you zoom in on the timeline so that there is not so much dragging. The Zoom tools are located at the bottom left side of the screen, to the left of the Storyboard / Timeline.