Photos missing in iPhoto but are in iPhoto library.

So some of my photos are missing from iPhoto when I start it up. These photos are missing from the general library and as well from the albums they were in. However if I go into the actual library through the finder the photos are both in the library and the albums. I have to tried to reimport these photos and I get this message: The following files could not be imported (they are unrecognized file type or the files may not contain valid data. I can not seem to find out what is wrong with these images since I can open them with any other program and they open fine. Please help