Full Screen Photos aren't showing in iPhoto

I have uploaded photos from my Photo Booth onto iPhoto. I can see the thumbnails, but whenever I go to full screen I just see a dark screen. The strange part is that I can still edit the photos, I just have to use the thumbnail picture as a reference. Does anyone have any ideas on how I can fix this?

I'd like to add that my Photo Booth has been acting funny as well. I can't see the photos as a thumbnail, just as a full screen. If I click on the empty spaces where the thumbnails would be they still appear on the Photo Booth's full screen.