Set a non-image mode as major mode in combination with image minor mode.
A non-image major mode found from `auto-mode-alist' or Fundamental mode
displays an image file as text. `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'
to display an image file as the actual image.
You can use `image-mode-as-text' in `auto-mode-alist' when you want
to display an image file as text initially.
See commands `image-mode' and `image-minor-mode' for more information on these modes. (fn)