bug#32672: 27.0.50; image resize on window resizing

[Juri Linkov]

>>      (add-hook 'change-major-mode-hook 'image-toggle-display-text nil t)
>>      (add-hook 'after-revert-hook 'image-after-revert-hook nil t)
>> +    (add-hook 'window-size-change-functions (debounce 
>> 'image-size-window-change 1) nil t)
>> +    (add-hook 'buffer-list-update-hook 'image-size-buffer-change nil t)
>
> Shouldn't you debounce the call to 'image-size-buffer-change' as well?
> After all, the buffer list seems to change more often than the size of
> windows.

When I tried debounce for buffer-list-update-hook, it used the last call
in sequence:

1 ... current: *scratch* ... window-buffer: *scratch*
2 ... current: *scratch* ... window-buffer: *info*

that was unsuitable for the logic of 'image-size-buffer-change'.

So maybe instead of 'debounce', we need to implement and use 'throttle'
or at least implement the 'immediate' option that uses the first call:

https://css-tricks.com/debouncing-throttling-explained-examples/

> In either case you probably want me to install the
> 'buffer-list-update-hook' changes.  Correct?

Yes, please install it, if you see no more regressions.