"I wonder if DAZ Studio processes RSR thumbnails inside the program."

Yes, as does Carrara. The rsr's are just Mac .pct images with a different header & some bytes at the end IIRC. Once you have a .pct, it should be simple to convert to .png using freeimage or another imaging library. Maybe one of the Python gurus could whip something up that you could use within Poser to convert the thumbs for the selected library folder?

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