|I've been searching around at length and didn't get very far - not surprising as Gretti has already done so.|
I don't think you will find anything that will make the conversion to the more usual jpg on either a Mac or even a PC.
It seems the only program that will open pza files is "MGI PhotoSuite". I did eventually find these cheap copies of V4 on Amazon so it could be worth risking a try:
I've no real idea whether it will do the trick and it is likely to need MS Windows, probably in Compatibility Mode as it certain to be for obsolete Windows operating systems.
If you can get the pictures to display in Windows then you could use a free screen capture program to save each picture (max screen) in jpg format. Once you have jpg's then you could presumably transfer them to your Mac.
I don't think there is any easy solution but if you manage to get the pictures to show on a Windows computer then I can assist with the capturing method.
Always pop back and let us know the outcome - thanks