The RAW Image Viewer is a simple tool for viewing digital photos in a few RAW formats: specifically, Canon CRW and CR2, Nikon NEF and Fuji RAF.
The emphasis really is on the word "simple", here. There's no thumbnail browser, no print option, no editing tools, very little in the way of extra features: the program can open files in these formats, zoom and rotate them, and save them again in more standard formats (JPG, TIFF and so on), and that's all.
Still, this does make the program very simple to use. Everything you need is available in a few toolbar buttons and you'll feel at home right away.
And, of course, many image viewers can't handle RAW formats particularly well, if at all, so if you work with these formats occasionally then a simple viewer (with a file conversion option) could be very useful.
Please note, while the program is entirely free, it will attempt to install the Babylon browser toolbar during the setup process. If that's not what you want then don't just keep clicking Next during installation: pay attention to what's happening, and once you get to the Babylon Toolbar screen, clear the relevant check boxes and it won't be installed.