well, I have done several dvd projects and i definitely can tell a difference between a high res and a low res on the screen. Keep in mind that dvd's have typically over 4 GIGAbytes and therefore can hold ALOT of stuff! I mean, we're talking an entire movie here!

I used my scrapbook stuff on my last slideshow, which we're talking about papers, elements, and photos on each screen. I kept everything at 300 dpi including scanned photos. I saved every frame at a maximum quality of 12 as well. I had 13 frames and only used about1/50th of the total DVD size! I don't know about you, but my slideshow program has a little picture of a cd at the bottom of the screen that slowly fills up as you ad images to the slide show so you can see how much you've used and how much you have left to work with. But I would say that unless you plan to put 500 photos on a dvd, you should be fine with saving at 300 dpi on maximum quality. I hope that helps you out! GOod luck!