I recently imported some photos into iPhoto. All was well, I keyworded them, and burned a CD of them just fine. Then today, I open it, and all the photos in this particular event show just an exclamation point rather than the photo. I tried rebuilding the thumbnails to no avail. I opened the iPhoto library package, and sure enough the photos are in there, and viewable by preview. I double checked the permissions, and I have R&W on them all. I tried to reimport the photos, and it says "the following files could not be imported (they may be an unrecognized file type or the files may not contain valid data)." Any have this experience?