No they don't. I've made both png's and rsr's for my stuff, and on my Pro pack it uses the png's. I can tell the difference coz I made special png's :o)

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You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.