Re: Image autodetection

[Richard Stallman]

    1. Make a new variable, auto-detect-image-type-p.  If non-nil, the
       function image-type-auto-detected-p (called from magic-mode-alist)
       performs content detection.  The default is nil.

    2. Do not display images as images automatically in image-mode.
       Instead, the user sees "Type C-c C-c to view the image as an
       image".  This additional step should not be a major inconvenience.

If we do #2, I see no need for #1.