bug#16062: [SPAM] bug#16062: 24.3; Missing .png file gives poor error message when opened

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 06 Dec 2013 08:57:04 +0100
> From: Jarek Czekalski <jarekczek@poczta.onet.pl>
> 
> W dniu 2013-12-06 08:18, Eli Zaretskii pisze:
> > How should Emacs know whether you intend to visit an existing file or
> > create a new one?
> 
> It seems so easy to determine what is the intention of visiting a png 
> file.

Is it?  What if I come up with an Emacs mode that lets users _create_
PNG files?

> But if Emacs admin does not know that, then I assume I make some 
> silly newbie mistake and it is in fact impossible.

I didn't ask the (slightly provocative) question to indicate that I
consider your request silly.  I asked it to put the issue in
perspective.  I agree it would be good to make the error message more
clear in this case, I just suggest that we think about the possible
alternatives to "File does not exist", because we don't show such a
message when users visit non-existent files.

IOW, I submit that the problem is with image-mode throwing an error in
this case, instead of showing "(New file)" in the echo area, just like
we do with any non-existing file.  We could also turn image-mode off
in such a case, although the correctness of that is less clear to me.