For the dng files I created with Lightroom 1.4.1 (importing .CR2 as dng), Snow Leopard (OS 10.6.4) is able to display a preview thumbnail in Finder and to open the files in Preview. It seems that no matter which backward compatibility options I select in DNG converter 6.2 (converting Panasonic .RW2), the resulting dng's cannot be previewed in Finder or opened in Preview. What gives? Is there a way to find out what kind of dng files are the ones that do work? I wish there was a way to find out exactly what flavor of dng (which specification, compressed or not, linear or not, etc.) a particular dng file is.