How many DVDs does it take to get a PhD?

My boss recently approved the purchase of a DVD burner for the lab, mostly do to my lobbying. Most of my research comes in the form of pictures of fly embryos. I spend a lot of time each day imaging my flies with the digital camera that is mounted on our microscope. And thus, I have hundreds of image files. Over 16GBs worth to be exact. Today I managed to consolidate all of my image data onto 4 DVDs (4.3 GB each). That's one for every year I've been a graduate student. 2 more DVDs to go? Your guess is as good as mine.