On Fri 08 Dec 2023 at 16:29:12 (-0500), Paul M Foster wrote:
> On Fri, Dec 08, 2023 at 11:04:54AM -0600, David Wright wrote:
> > On Fri 08 Dec 2023 at 11:56:12 (-0500), Paul M Foster wrote:
> > >
> > > I'm on Debian bookworm, using neomutt for email. Where there is an image
> > > to
> > > view, viewing it in neomutt calls up one of the ImageMagick programs.
> > > I've set
> > > the mailcap_path variable in my neomutt config to point to ~/.mailcap,
Similarly, I point it to ~/.config/mutt/mailcap-mutt, which is
a specially crafted subset of /etc/mailcap with a few additions
(like converting webp to a jpeg rather than opening in gimp,
and playing midi files the way I want).
> > > and
> > > set an entry in there for image/jpg to point to /usr/bin/feh. I've even
> > > set
> > ↑↑↑ try jpeg
> >
> > > the "display" alternative to feh with update-alternatives. Still, mutt is
> > > calling an imagemagick program to display jpgs.
> > >
> > > First, if alternatives doesn't point to the imagemagick program, and the
> > > mailcap file doesn't point to it, and there's nothing in the neomutt
> > > config
> > > pointing to the imagemagick program, then where the heck is it getting
> > > that
> > > as the program to use to display images?
An email would contain headers with the attachment.
↓
Content-Type: image/jpeg
Content-Disposition: attachment; filename="don.jpg"
Content-Transfer-Encoding: base64
By default, mutt searches six directories for a mailcap file. When
found, the line in the mailcap starting with image/jpeg selects the
program to run.
If you see an extension in a mailcap field like nametemplate=%s.jpg
that's to show that a filename matching that pattern should be given
to a copy of the attachment to satisfy the program that's going to
read it. But it's the attachment /content type/ that selects the
program, not the extension¹.
> > > Second, how do I fix this so that mutt uses feh to display images?
>
> I can't believe that worked. The /etc/mailcap has both (jpg and jpeg), and
> the files I was looking at had a "jpg" extension.
>
> But thanks for the tip.
A couple of programs in my /etc/mailcap (gpicview and gm) have
image/jpg lines, duplicating the image/jpeg entries, perhaps
as a "catch-all" for malformed emails containing image/jpg.
I don't know whether image/jpg is an official legacy type/iana-token.
¹ Re the argument raging in this thread about "extension", the
term is clearly appropriate, as a glance at /etc/mime.types
demonstrates. The literature is full of the term.
I wouldn't want to use "suffix" myself, as it's too general:
anything stuck on the end is a suffix, but not necessarily
a filename extension. Suffixes are used for other purposes.
Cheers,
David.
