When I open iPhoto it shows thumbnails of all of my photos, just like it should. I have ~950 photos. Maybe one hundred or so (it seems to be just 2 rolls) do not display when I double click them. I open them up and I get a square with an exclemation point in the middle. I have gone to these photos in finder and opened them with preview and they open fine. I don't know why iPhoto doesn't want to open them. Has anyone else ever seen this?