Below you can see the front-view size comparison of the Olympus E-PM1 and Olympus E-M1 II. The Olympus E-PM1 is clearly the smaller of the two cameras. Its body is 24mm narrower, 27 mm shorter and 33 mm thinner than the Olympus E-M1 II.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.