Why did I lose picture quality going from iPhoto to iDVD?

I created a slide show on iPhoto and exported it to iDVD. This is my first time using iDVD, but I managed to create a wedding theme with a few photos, followed by my 102 photo slide show. I burned it to a DVD. When I play the DVD back on my computer, or on my television, the picture quality is noticeably inferior. (At first I thought it was just the TV so I played the DVD on my computer.) The pictures on my iPhoto slide show are razor-sharp with vibrant colors. The DVD slide show photos played on the same computer are fuzzier and dull in comparison. When I look closely at the screen it looks a little wavy. Is there anything I can do about this? Thanks!