Q: exclamation point in imovie?

Thank you to everyone reading.

I recently upgraded my macbook pro to OS X El Capitan and one of the new things is the new Photos app which has replaced iPhoto.

The problem is with imovie. Today i went to edit a project that i had done last month but there is a little yellow triangle with an exclamation point in it, on every single video and soundtrack. It claims it can't find the clips i have to modify. I have already researched online what to do, everyone says that it can't find them because they have been moved, so i should move them back. But the clips are in photos and i haven't got iPhoto anymore, so i don't know what to do. I have also tried re-uploading the clips in iMovie's library but that didn't work either. Please help!!