Adding a photo/still image to start of movie freezes on that image and doesn't transition to rest of movie

I have basically completed my movie with images, audio clips and background audio. I want to add one more still image to the start of the movie but when I do that and try to play my movie, it freezes on that one image I just added (yet continues to play the audio for the rest of the movie). I took my problem to the Apple store today and they had no clue how to fix (said it must be a bug) and just suggested I export the movie then import it again into a new movie. But when I do that I lose the quality of the images considerably. I am 99% done with the movie and just need this title image inserted in.

Any ideas why this might be happening or how to resolve without re-building the entire movie again?