Why Do Identical Image Numeric Filenames Change & Why are the photos sorted weirdly?

When I look at a string of images that I have taken, I am finding some interesting & confusing results. I have a LOT of examples, but will try to make this as easy as possible. Scrolling through the "Photos" app on my Max Studio, I have found a lot of these confusing numbering difference even though the photos are identical in EVERY aspect. Here is just ONE example...

I have an image "IMG_1586.JPG" & another "IMG_6843.JPG" that are identical pictures. If I ask for Info, I get the exact same information (everything). Why is that?

Also, In a lot of my Photos, I will find that a numbered image (example: IMG_0486.JPG) will appear in the "Photos" app before an earlier image (example: IMG_485.JPG) and it might even several images later like this... IMG_486.RPG -> IMG_487.JPG -> IMG_488.JPG -> IMG_485.JPG. Why is that? And I can't changed the sort Method.