Pentax Optio WG-1 GPS Operating Manual page 50

The size of a recorded image differs depending on the number of
recorded pixels of the images. This affects the number of images that
can be saved on an SD Memory Card.
Choose the appropriate number of recorded pixels for still pictures on the
[1_1Rec. Mode] menu.
Selecting the Number of Recorded Pixels _÷p.125 ]
Choose the appropriate number of recorded pixels and frame rate in
[Movie] on the [1_ Rec. Mode] menu.
ISelecting the Number of Recorded Pixels and Frame Rate for Movies
_÷p.152
For an approximate guide to the number of images or the length of
recorded movies that can be saved on an SD Memory Card, see "Main
Specifications" (p.298).