On 19 Sep 2018 05:35:46 GMT, Arlen Holder wrote:

Certainly there must be a REASON why Windows is capriciously opening files.
But what?

As a test, which failed, I installed Fast Stone Image Viewer version 6.4
http://www.fastone.org/FSViewerDownload.htm

I selected a dozen files named with numbers on the end
http://www.bild.me/bild.php?file=1623177faststone002.png

The good news is they opened in the expected numerical order in FastStone
http://www.bild.me/bild.php?file=9848098faststone001.png

Why does FastStone work as expected, but not Paint.NET nor Paint?

Unfortunately, I've been editing screenshots for decades where nothing
comes close to Paint.NET for DYNAMIC editing of curved arrows, bounding
boxes, and text so even though I hate NET Framework, I'm stuck editing with
Paint.NET because nothing is anywhere near close (not even Pinta).

Trying to get FastStone to feed the files in order to Paint.NET
http://www.bild.me/bild.php?file=2153814fastone001.png

I hit FastStone: Edit Edit with External Program Add/Remove Programs
http://www.bild.me/bild.php?file=1224536fastone002.png

I hit "Add", and found the Paint.NET executable, and hit "OK", "OK".
http://www.bild.me/bild.php?file=1886841fastone003.png

I pressed "control+a" inside of FastStone:
http://www.bild.me/bild.php?file=3734808fastone004.png

Then FastStone: Edit Edit with External Program PaintDotNet (E)
http://www.bild.me/bild.php?file=2563105fastone005.png

Unfortunately, that only edited a single file, and not the selected set.
http://www.bild.me/bild.php?file=5840435fastone006.png

So that was a bust.

If we could figure out why Paint and Paint.NET get the file order
capriciously, we could begin to solve that pesky problem.