One slightly off-the-wall thought: what's the status of your video driver? I have an Nvidia GeForce card, and the built-in latest-drive functions in Windows, pointing to Microsoft, load a very old driver. When I bought Hexagon on that DAZ special offer, I had to go to Nvidia's website to get a properly up-to-date driver. and doing that made Poser run better as well. As far as saving a specially-made PNG goes, you are rendering to the the right target size? I use 91x91, though I'm not sure where I got those figures from. And, with the Poser colour choices, it's sometimes all to easy to misread a filename so that the rendered version is distinct from the auto-generated version.