It could be done, but it would take quite a bit of work for a low-res image. Think of it this way.... If you're making a DVD slideshow, it's usually converted to an actual DVD 'video'. That data is displayed on your TV screen at 480p resolution in TV speak. That resolution is about half of 1024x768, if that helps.
So if you're worried about copyright issues, etc, you're pretty much set. To be a little extra certain, you could use a lower res image for the DVD project to begin with, and printing would be worthless anyway.
If you're wanting to offer the files for printing, you *may* be able to put the files on a different track, sort of like an audio track on a CD...but I've never tried that with a DVD and I'm not sure if it's even possible. If you are wanting to offer them for printing, you could always offer the slideshow on DVD and the full-res images on CD - blank CD's are cheap these days.