A Bug related to ImageTk in Python on Cygwin

[Friedrich Romstedt]

Hi,

Some months ago (in August 2021) I tried using ImageTk in Python on
Cygwin and stumbled over a dysfunction.  To help tracking down the
issue I wrote up an HTML document and uploaded it to
https://github.com/friedrichromstedt/bughunting-02.  There is a
minimal Test Case included in this github repo.

I updated my whole Cygwin installation just this moment and found the
behaviour unchanged with respect to what I've observed that time.

Any pointer would be very much appreciated.

Best,
Friedrich