hello. i'm not familiar with the .pza file but try using acdsee. for me its the best picture viewer out there and it can also convert, resize, most picture format.
I can tell you of a great program that will do more than most photo programs costing 2 to 3 times as much. It is "Photo Impact Pro 8.5" from U-Lead software. I have about 15 edit programs and this is the one I keep going back to. It is pretty easy to learn also, One of the few that comes with a real book. I call it the "Photo-Bible" Good luck. http://www.ulead.com