You're close. Poser 4 (PC version anyway) requires .rsr files. Poser Pro Pack and Poser 5 both use .png files instead. If there are no .png files, Pro Pack and Poser 5 create them from any existing .rsr files (which you could then delete). So as long as you have .rsr files, you're all set for any version of (PC) Poser. If you're on a Mac, you should be using Mac Converter.

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