HP R717 - Manual (Page 35)

35 Taking Pictures and Recording Video Clips
Orientation Sensor
An electro-mechanical device in the camera determines
whether the camera is being held horizontally or vertically
when a still picture is taken. The camera uses the reading
from this sensor to automatically rotate the image to its
proper orientation when saving the file.
TIP: You can also manually rotate still images using the
Rotate option in the Playback Menu. See Rotate on
page 102.
NOTE: The orientation sensor is not used when recording
video clips, nor in the Panorama or Document shooting
modes.