Attached Link: http://www.renderosity.com/mod/bcs/index.php?ViewProduct=72056&keyword=p3do

As TrekkieGrrrl said, P3dO has a PZ3 3D viewer and all kind of Poser files as well (CR2, PP2, HR2, even PZ2) compressed or not, zipped or not.

You have the ability to save a thumbnail from the P3dO render and thus create/override the Poser thumbnail.
You can also set that thumbnail from any Poser Render as Tashar59 said.
 
Once the PZ3 has a thumbnail P3dO will show both the PZ3 and its thumbnail in the same cell (as it does with other Poser files).

Limits:
The PZ3 render in P3dO is not accurate. It is not as complete as Poser render, so don't expect P3dO to be able to display complex scenes. But you will be able to figure out what is in the PZ3.

Yarp

Yarp - author of P3DO Organizer for Poser