RAW, which is a popular file format for higher-end digital cameras and digital SLR cameras, contains the raw sensor information without any modifications made to the file. This format is very popular with photographers, as you can adjust things like white balance (to get accurate colors), change exposure (make an image brighter or darker) and adjust noise reduction and processing details. The major problem with the format however, is that unlike JPG images which you can preview in Windows Explorer, RAW images usually show up as a generic icon and not a preview image.
Microsoft’s Camera Codec Pack will allow you to preview these images so you don’t need to open every file individually to see what is in the photo. The photo below shows what RAW images will look like when you open them on an SD card before and after the codec pack is installed.
You can download the Microsoft Camera Codec Pack by clicking here  and choosing the x86 version for 32bit computers or the amd64 for 64bit machines.