There are no automatic ways to match your slideshow to the beat.
However, once you've created your slideshow and added your music track, there is a way to adjust the overall page of the slideshow, if that's what you're looking for.
1. Make all your slides the same length, between 4-6 seconds. Add your music track and adjust so they end together. The brain will perceive the two to match because of the brain's strong proximal association. You will be amazed how well it works the first time you see it.
2. Match the visuals to the music, not the other way. You can use downbeats, dynamics, or transitions as marker points, and you don't need a lot of them. Comes pretty easy after a couple of tries.
Here is a quick video project of mine that uses method 2.