bug#65188: 29.1; WEBP image not displayed

[Eli Zaretskii]

> From: awrhygty@outlook.com
> Date: Thu, 10 Aug 2023 09:20:52 +0900
> 
> 
> I installed emacs 29 from:
>   https://ftp.gnu.org/gnu/emacs/windows/emacs-29/emacs-29.1_1-installer.exe
> When find-file with WEBP images, they are not displayed visually,
> and emacs reports:
>   Cannot display image: (Invalid image specification)
> There exists c:/Emacs/emacs-29.1/bin/libwebp-7.dll in the same directory
>  of emacs.exe.
> 
> image-types
> => (bmp svg webp png gif tiff jpeg xpm xbm pbm)
> (image-type-available-p 'webp)
> => nil

This might mean your libwebp-7.dll is incompatible with Emacs you have
(e.g., it's a 32-bit DLL, not 64-bit DLL), or Emacs cannot load it for
some other reason.

Corwin, can you please verify that the binary on the GNU FTP site can
display WebP images when a suitable libwebp DLL is available?  The
Emacs 29.1 I built myself here is definitely capable of displaying
WebP images.