Slideshow adds duplicate pictures

Ok, here goes. I’ve got over 900 pictures that I made a slideshow with. I added transitions and music. I burned the disc, popped it in my DVD player and WOW! it was awesome…until I started noticing that there were pictures repeated in the next few chapters. I thought I did something wrong so I redid the whole damn slideshow. Start to finish. I made sure I wasn’t picking up the same pictures twice. Burned it and AGAIN I have duplicate pictures. Anyone know what’s going on? :a