This format is used to create images without compression on Nikon Coolpix cameras. The created RAW files contain electronic data from the camera sensor. It is able to save more data compared with compressed photos. With NRW files you can set the exposure, white balance and other settings while preserving all the details in the image.
ICO is a file of this format usually contains a small image icons of different resolutions (16x16, 32x32, 64x64 pixels) and various color depths (16 colors, 32, 64, 128, 256, 16-bit, and so on). Used to display files and folders in the graphical user interface (GUI) operating systems. This format can be opened with the help of the program ACDSee.