Nikon D750 User Manual page 270

Rotate Tall
A
To display "tall" (portrait-orientation)
photographs in tall orientation, select On for
the Rotate tall option in the playback menu
(0 308).
Image Review
A
When On is selected for Image review in the playback menu (0 307),
photographs are automatically displayed in the monitor after shooting
(because the camera is already in the correct orientation, images are
not rotated automatically during image review). In continuous release
modes, display begins when shooting ends, with the first photograph
in the current series displayed.
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