by mrmacfixit Moderator - 2/2/13 10:39 AM

In Reply to: iPhoto many fuzzy photos by djohlson

could be because the original photo is not found and what you are seeing is the enlargement of the thumbnail picture.
The exclamation point indicates that iPhoto has no idea where the original is.

iPhoto 11 is the current version of iPhoto, it may be worth springing for that but, in the meantime, drag out your trusty Time Machine backup and go back to when all the pictures were good.