What is a ICO file
Files with the ICO extension are commonly used by the Microsoft Windows operating system in order to display a picture that is used for a computer icon. It can be used for item icons in the start menu, shortcuts, directories, or for programs. In order for the computer to associate a picture with a certain file or program, it is mandatory to use a file with the ICO file extension. The ones most commonly known are, among others, the small computer icon on your icon used to direct you to the "My Computer" directory, or some kind of sheet or notepad which is commonly associated with different word processing programs like Microsoft Word, OpenOffice Writer, or Notepad.
ICO files have been part of the earliest versions of Microsoft Windows already. Over the time, the file format has evolved and improved when it comes to color support or maximum size of pixels allowed. Currently, in the Windows 7 standard, the icons can be up to 256 x 256 pixel in size and incorporate 8 bit transparency and 24 bit color.
Here's a small, but not exhaustive list of programs that can open ICO documents:
- Adobe Photoshop
- Microsoft Paint
- Windows Picture and Fax Viewer