Below you can see the front-view size comparison of the Fujifilm Z900EXR and Panasonic GX85. The Fujifilm Z900EXR is clearly the smaller of the two cameras. Its body is 21mm narrower, 12 mm shorter and 26 mm thinner than the Panasonic GX85.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.