Preview finds no images to import
I'm trying to use Preview on my MacPro desktop to import images from my iPhone. I'm following the instructions on Preview (El Capitan): Import images from a camera, but the pane that should show the images on my iPhone is empty. There are thousands of photos on my iPhone, and it is on and unlocked. Why can't I choose any photos to import?
VIN,Mac Pro (Early 2009), OS X El Capitan (10.11.1)