Re: C file recoginzed as image file

[Richard Stallman]

      7) Use a "disabled" wrapper for image-mode (or image-mode-maybe) in
    `magic-mode-alist', so the user is forced to decide whether he trusts
    auto-detection or not (I just dreamed this one, and I'm adding it out
    of completeness, but I don't like it).

That might be a good alternative.  The usual disabled command feature
lets you enable the command either once or permanently.

If not that, then we should simply disable it.