Hello, I have a new imac with iMovie 09. I recently downloaded several mp4 movies, and they play in Quicktime. I have attempted to import them into iMovie, and it says they have imported, but there aren't any thumbnails. I've seen a few threads here that mention using other converters to try to resolve this problem. Can I do this with downloaded video? I'm new to the imac. Or is there an easier way to fix the import problem? Many thanks in advance.