too many files open

[DPaul]

Currently, you're trying to open a huge slug at a time.

Hi Larz,
I already tried with open(...) as ... but it gave no results.
Also I closed all files, or set them to "None"... everything failed.

Although the numbers are huge, in principle I open only 1 file at the time, cut it in max 4 parts,
save them, and close everything. But it would seem that the img.save operation keeps its filepointers somehow.

While executing my "Plan B", I have come to suspect a difference between win 10 and win 11.
My Plan B works on win 11 but not on win 10, with the same error24.

If by chance I find a reason why, I will publish it.
Is it Python, is it windows ? Am I barking up the wrong tree?
Paul