A legacy format with RAW structure for storing photos taken with Canon cameras. It contains graphical information about data that was obtained through the lens without the use of hardware or software correction and compression. It contains metadata that identify shooting conditions and camera settings.
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.