image-mode-fit-frame
image-mode-fit-frame is an interactive compiled Lisp function in `image-mode.el
'.
(image-mode-fit-frame &optional FRAME TOGGLE)
Fit FRAME to the current image.
If FRAME is omitted or nil, it defaults to the selected frame.
All other windows on the frame are deleted.
If called interactively, or if TOGGLE is non-nil, toggle between
fitting FRAME to the current image and restoring the size and
window configuration prior to the last `image-mode-fit-frame'
call.