bug#54242: Emacs can't display animated webp images

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: 54242@debbugs.gnu.org
> Date: Sun, 10 Apr 2022 15:54:22 +0200
> 
> > Now it builds and works on MS-Windows , but can you point me to the
> > animated images you used to test, so I could see that it works
> > correctly on Windows?
> 
> I've been using a HTML file containing:
> 
> <img src="https://mathiasbynens.be/demo/animated-webp-supported.webp";>
> 
> And visiting it with eww, because that's the easiest way to ensure
> triggering the animation machinery.

It seems to work, but flickers like dickens.  Is that expected?