In iDVD 6, your slideshows are no longer limited to 99 images. You can now have up to 9,801 images in a slideshow. If you add a slideshow to your iDVD project with more than 99 images and an audio track, you may notice that the audio drops out very briefly after the 99th slide on your burned DVD.
That's alot of pictures. In fact, that may be reason enough to get iLive 06.