bug#38187: 27.0.50; No mouse-wheel scaling on images

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Eli Zaretskii <eliz@gnu.org>,  stefan@marxist.se,  38187@debbugs.gnu.org
> Date: Thu, 21 Nov 2019 22:26:30 +0100
> 
> (dolist (file (directory-files dir-with-lots-of-images))
>   (erase-buffer)
>   (insert-image (create-image file)))
> 
> You get the same effect by altering the scaling factor, I think?  Each
> scaled image is cached?  So by rolling the wheel ten clicks you get ten
> cached copies of the image.

Again, does binding redisplay-dont-pause to nil help in any way here?

> A better eviction algorithm would be nice.

Such an algorithm would need to detect these "useless" cached images
to be effective.