Trying to proceed, a correction to above. There seems to be an algorithm where of the approx ten frames in the video, the phone chooses the key image, may be any of the 10, it doesn't default to the first frame. Seems to know to avoid choosing the frame with closed eyes in this selection process, and chooses for lightening also.

Duplicating a new key image seems to create extra folders on the iPhone, I now have created somehow 9 new folders for September, and images are being duplicated in the various folders, the same images are in a and b for example. Getting the pics off the phone via cable will be nigh impossible with all of these folders and duplicates. I will use iCloud which should be easier, but for some reason when I choose a different key image on the phone I end up with 2 of those files in iCloud. So in downloading to my PC looks like I will get duplicates, but just 2.

Answering my own question, unless using a Mac and retaining the images in their original format, it is way preferable to just set the camera to take jpgs and then take several to get different frame choices for people and lighting.