Function: image-minor-mode

Toggle Image minor mode in this buffer.
With a prefix argument ARG, enable Image minor mode if ARG is
positive, and disable it otherwise. If called from Lisp, enable
the mode if ARG is omitted or nil.

Image minor mode provides the key
Uses keymap `image-mode-map', which is not currently defined.
M-x image-toggle-display,
to switch back to `image-mode' and display an image file as the
actual image. (fn &optional ARG)