RAW pictures are high-quality, uncompressed files that differ by camera manufacturer. Some common file name extensions for RAW picture files include: .cr2, .crw, .dng, .nef, .orf, .rw2, .pef, .arw, .sr2, .srf, and .tif.
Download --> RAW Codec Drivers allow Windows 7 to handle RAW image files with the same ease as JPEG or TIFF images: