Thank you so much Brian:
You need to set your default photo application to photo gallery. Settings->System->Default Apps->Photo Viewer and pick Photo Gallery from the list once you click on the current app (which is probably the Win 10 Photos App) to bring it up.
*I did these steps and chose Photo Gallery, but on clicking on it, it showed a new dropdown with: “Paint”, “Movie Maker”, “Windows Photo Viewer, and again the Photo Gallery. Was I to click on one of these too? There was no “OK” button, but I hope it's now the default.
You don't "transfer" your pictures from app to app and you don't likely have duplicate copies. Either Photo Gallery or the Win10 Photos App generally look in the Pictures library to locate the images you have unless you make an effort to customize things.
*I understand now. I still don’t know why and how to get rid or prevent getting unknown photos, but if I won’t need to use the Photo App then there’s no problem, right?
I do not recall whether Photo Gallery has an upload feature to it as I have never used it. I currently use Fast Stone Image Viewer as my default photo app and can control precisely where I want things uploaded from either a camera or a card reader from within that application.
*Thanks for mentioning ‘Fast Stone Image Viewer”, I took a pick and it looks like a thorough and easy system....of course it’s the opinion of a very beginner in computer things lol.
I can't comment on what's happening with your e-mail application as there's not enough information to go on.
*Oh I have the worst desktop email: WLMail but I like the “bells and whistles” it offers but it has deteriorated and without support, and I’ll try to change to Thunderbird as soon as I can. ;)
*Thank you again and I will try now to upload a pic to see whether it will land in the Photo Gallery and I'll report it here. If it doesn't work for me, maybe I'll venture to try the Fast Stone Viewer and hope I won't be messing it up in the process...
P.S. I see in posting this, the color and font I used to distinguish my answers disappeared, so I'll put some space and an asterisk.
P.P.S. Where in the control panel here I can configure to receive notices of the answers?