Down a tech rabbit hole

I am a bit embarrassed about even asking this.  I am not a complete troglodyte but not exactly a technophile either.  It seems simple but then it becomes a bit like a logic puzzle and I am stumped.    

When I started microing again in '20 I was using a Dell I bought in 2016.  After replacing the hard drive with an SSD, it worked well and never slowed down.  I was using the Paint that came with Windows 10 and Paint.net.  While I saved micros to .png files (before making gifs to post), I also started saving them to MS OneNote. If I downloaded a micro, I used it because the background would turn black it I took it to Paint.  Plus, it is actually easier for me to organize them by project or phases of development.  I Frankenstein and change a lot just to so how something looks.  Some of those .png files would get in the 300-inch (35000-pixel range).  Out of that, I may only have 3 or four things I want to keep, so I would store it in OneNote to find it more easily. The images went back and forth between Paint and OneNote without any issues.    

But then I decided to get a new computer to improve my connectedness for work.  Once everything was set up, I tried some microing and ran into a problem.  When I tried to save the decent stuff to OneNote, everything was smaller than what was on the OneNote page from before.  So I tried to reverse and brought the new images back to Paint.  No problem.  So I brought the older image from OneNote into paint and found that not only was the old image bigger but had dithering (sp?) too.  Here is an example:


At first, I thought it was a Paint problem - maybe the newer version was to blame - but the same thing was happening in Paint.net and I was using the same version on both machines.

So then I decided to check the resolution and it was different:
      Old:       1366x768    (recommended) at 100% (recommended)
      New:     1920x1200   (recommended) at 125% (150% is recommended)

So, I thought that was the problem.  I reduced the new machine's resolution and was able to transfer micros from OneNOte to Paint at the proper size.

But then I thought to check what this looked like on another device.  So I put the previous image on a new OneNote page on my phone.  I then navigated to the page on OneNote note where I was storing this micro, copied it, and pasted it into the new page next to the previous image:

Despite all starting as the same image stored in a .png, in order they are:  
1)  the original image from the new computer Paint app;
2)  the image from the new computer OneNote app moved to Paint.net;
and 3)  the image from one page in my phone OneNote App to this page as it appears on the new computer OneNote app.

and 4) this is the same image above screenshot from the OneNote app on the new computer and overlaid on the previous image.


And this is why I can't get my head around the issue:

a) If the issue was just the difference in resolution between the two computers, then there shouldn't be a difference between image 1 and image 2 because the new resolution would affect both equally; but

b) If the issue lies solely within OneNote, images 2 and 3 should be the same as they both came from the same picture within OneNote and would not be affected by the new computer; but

c) If the issue was just that the OneNote app on the new computer was adding size then the characters within image four should not be the same size. Reviewing it through the OneNote app on the new computer and pasting it into Paint on the new computer should have, again, added size.  

And there you have it.  

. . . and the cat that was smiling at me just disappeared.