Using multiple tracks on a slideshow but songs overlap after being shortened

I made an imovie slideshow of 130 or so photos and used about 5 tracks from iphoto with start and finishes at certain photos in the slideshow. I used the clip trimmer to trim front ends of tracks and i used the arrow bar on the track to end the song as the next one starts, sometimes with some overlap. When I played it in the viewer numerous times while editing it and before export/saving the file, the music played correctly and the track would end where I shortened it to. But on the exported/saved file, the track keeps playing over onto the next track.