I'm not sure what Nikon do, but with canon you get DPP in the box, which can act as a browser and displays RAW thumbnails (with "RAW" in little letters if it's a raw). Does Nikon provide such software?
Chris
If you are talking about NEF's, then all you need to do is download and install the Nikon CODECs.
http://www.nikonimglib.com/nefcodec/
I use Picasa to preview... But it can do odd things to the colours/brightness...![]()