Microsoft Windows Icon (.ico)
The ICO file extension, standing for "Icon", is integral to Microsoft Windows for storing icons of different sizes and color depths. Its primary use is to display graphical representations of executable programs, files, and folders within the Windows operating system. The ICO format's origins trace back to the early versions of Windows, evolving over the decades to support enhanced resolutions and alpha transparency. Today, ICO files ensure visually consistent and scalable icons that maintain their appearance across various display settings, aligning with modern user interface standards.