Nikon D300 User Manual page 86

Image size is measured in pixels. Choose from the following
options:
-2 Print size in inches equals image size in pixels divided by printer resolution
in dots per inch (dpi; 1 inch = approximately 2.54 cm). Print size decreases as
printer resolution increases.
Image size can be set by pressing
the QUAL button and rotating the
sub-command dial until the
desired option is displayed in the
control panel.
QUAL b utton Sub-command
dial
r ]
Q
Control panel
6O
[] The Image Size Menu
Image size can also be adjusted using the [Image size] option in the
shooting menu (pg. 254).