Ron... Here's some background on the Unisys GIF patent, and why people might want to stop using GIFs: http://burnallgifs.org/ And here's some background on the PNG format: http://www.libpng.org/pub/png/ Poser 4 uses RSR format for the thumbnails. It is almost the same as the MAC PICT format, with an extra header and trailer. The RSR Converter program, which is available in the free stuff area, converts back and forth between RSR and PICT. I don't know why Pro Pack changed from RSR files to PNG files for the thumbnails, but I always assumed it was because they wanted to go to a more mainstream file format. (Nothing I know of, other than P3DO and RSR converter, knows how to deal with RSR files.) Each time you open a directory in Pro Pack (for example, you select "Figures/DAZ People"), Pro Pack creates a PNG thumbnail for each RSR thumbnail in the directory that doesn't already have a PNG counterpart. After that, it never looks at the RSR file again. So you don't need the RSR after that. And if you install an updated version of the product with an updated RSR file, Pro Pack won't look at it until you delete the PNG file, and access the directory again. (That's why we ship both PNG and RSR thumbnails with our products.) By the way, there is another form of RSR files that contain geometry. Poser 4 (but not Pro Pack) converts OBJ files to RSR files the first time you access them. There are two ways to tell them apart: - Thumbnail RSR files are small (around 10K); Geometry RSR files are much larger. - Thumbnail RSR files live in directories under the Runtime/libraries subdirectories, while geometry RSR files live under the Geometries subdirectories. Hope this helps.... Lynn Grant Castle Development Group