Subject: bug#16515: 24.3; Images do not automatically revert on file modification when auto-revert mode enabled for image-mode.

From: Michael Heerdegen <[email-masked]>
Date: Tue, 21 Jan 2014 22:12:47 +0100

Michael Heerdegen <[email-masked]> writes:

> > (add-hook 'image-mode-hook (lambda ()
> >                               (auto-revert-mode 1)))
> >  
> > Next perform the following steps:
> > 1) load a PNG file (opens in image-mode buffer)
> > 2) modify PNG file
> > 3) notice that PNG in image-mode buffer does NOT automatically revert
>
> More precisely, reverting happens, but after it the image is displayed
> as text (at least that's what you said in gnu.emacs.help, and that's
> what I see).

When adding

  0)  (auto-image-file-mode +1)

to the recipe, reverting happens as expected.  I must admit that I don't
understand this.  Why does `auto-image-file-mode' help here?  And why
does emacs -Q display a png automatically as image when finding it
although `auto-image-file-mode' is off by default?

Michael.