Re: Image-conversion shims

[Juri Linkov]

> I.e., we want ("*.webp" . image-mode) in auto-mode-alist, but we can't
> put it there before we've called "gm convert -list format", and we don't
> do that until we call `create-image' with image-use-external-converter
> non-nil, which won't be called since we don't have a mapping from
> "*.webp" to image-mode.
>
> Very chicken and egg.
>
> Hm...  One possibility would be to do away with
>
> (setq image-use-external-converter t)
>
> as a user-level thing, and instead tell them to do
>
> (image-external-converter-mode)
>
> in ~/.emacs, which would do the probing and then altering
> auto-mode-alist.  Hm.  Perhaps that's a pretty clean idea?  Hm...  I
> think so.  Except that switching the mode off would have to remove the
> entries from auto-mode-alist again, which sounds slightly destructive.

We already have a working solution with imagemagick-register-types,
imagemagick-types-inhibit, imagemagick-enabled-types, and all related code.
Customization should be no different when images are handled via a process
instead of using a linked library.