Iforbes:
Thank you for your reply. I meant to mention that I have Office 365 on my personal machine (with the separate install of OneNote). It's my work machine that's at issue with the shrinking images in the full Office 2016 Professional Plus installation. And this is a consistent problem I've seen for years in Office 2016. Installing my own Office 365 at other jobs in the past -- is the only way I got around this problem.
As to your point about OneNote being included in Office 365 now: If that's the case, that's part of the change that Microsoft made in putting OneNote back into Office (365 and future versions). They removed it from Office 365 -- so the only way you could get it was a full OneNote 2016 installation (or an Office 365 install with a separate install of OneNote).
So what you're seeing now in Office 365 reflects that change. On my account it still shows that OneNote isn't included in Office 365, but on this page it is -- which syncs with what you're saying: https://www.microsoft.com/en-us/microsoft-365/buy/compare-all-microsoft-365-products
That's good to know -- because now I know that a standard Office 365 install (with OneNote included) -- does not have the problem. So your input has been helpful -- it's just that it doesn't solve my problem (because at work I'm stuck with Office 2016 for now).
I really do appreciate your input on this -- and please let me know if that clears it up and if you have any further thoughts on it.
Thanks!