For the sake of simplicity, let's say I need a slideshow with ten slides where each slide needs to be displayed for exactly one minute and each slide needs to have it's own song.  

How can I tie a specific song to a specific slide without it exceeding to the next slide?

I'm using iPhoto.  Adding songs is simple enough, but cannot figure out how to limit songs to their specific slides.  Shortening the song in iTunes to the duration of the slide is simple prior to adding it to the slideshow does not seem to carry over the limitation; it brings the full song.  Perhaps I am using the wrong tools.

Try iMovie instead. It’s free.

Thank you.  Never used that before, but it's working very well for what I need to do.