Originally posted by SemperFideles
Yes. You can fit 4.7GB of data files on to a DVD disk. That is the equivalent of about 7 CD's. When the dual layer DVD media becomes more affordable you'll be able to burn about 8 GB (12 CD's) to one disk.
I would not rely on this as your only method to archive your images. The mylar in optical media is known to break down over time and, 10 years from now, you may find your information is totally gone.
I've been taking digital pictures for 7 years now. I probably have about 100,000 images. I store them all on 3 hard drives. They're all duplicated in full on all three using file sync software. If one hdd fails then I have a backup. I've also begun to backup my system using Carbonite. It's an online backup system that only costs $5 a month and backups in the background.
Anyway, a long answer to your question. I don't have a problem with backing up to DVD media as a method. It's a good method but make sure she has another way of archiving the data.