Well, I just ran into the same problem again. I never used to have a problem plugging my iPhone into my laptop with Photos running. It would show up right away. Now, coming back to do it again, it once again won't work. You mentioned Image Capture. When I look in Launchpad, I don't see it. I searched for it in Finder and clicked on it and it just said no camera was attached (though my iPhone was attached). Where might I find it, to check settings or whatever.
Thanks.
BTW, all my photos are on an external drive, which is attached to my MacBook Pro before I load Photos. This never mattered before.