Below you can see the front-view size comparison of the Pentax WG-3 GPS and Ricoh WG-50. The Ricoh WG-50 is clearly the smaller of the two cameras. Its body is 2 mm narrower, 2 mm shorter and 3 mm thinner than the Pentax WG-3 GPS.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.