Reference Manual

191D The Playback Menu: Managing Images
If On is selected, “tall” (portrait-orientation) pictures will be
automatically rotated for display in the monitor (pictures taken
with Off selected for Auto image rotation will still be displayed
in landscape orientation). Note that because the camera itself is
already in the appropriate orientation during shooting, images
are not rotated automatically during image review.
Rotate Tall
G button ➜ D playback menu