videos from iphone importing as JPG

hello - having much difficulty importing from iphone and have for a long time. the import proces seems to complete but the progress bar is stuck at halfway and stays that way forever. not to mention the numerous errors about file types and dynamic link servers. but i've researched those issues on here extensively. but now, when i import videos, they come in as jpgs. when i hit 'show in finder' it shows me a jpg image, of a file i know was a video. the jpg thumbnail is the first frame of the video. trying to purge video cache currently, that process seems to be just hanging tho. its been about an hour. i thought next i'd try to uncheck the box that says 'limit video cache size.' as i have a large library. any help is appreciated.