The ICO file is an icon storage format in the Microsoft operating system. This file extension is an image format and may contain file, program and folder icons in the Windows system. This file format consists of two bit images, one of which is an image mask (AND), and the second is represented as the icon itself, displayed on the mask (XOR).
The user can edit ICO files in order to generate special icons. ICO format can save files with JPEG and PNG extensions. Due to the fact that Microsoft Windows is very popular, this file format is very important. Any icons within Windows, regardless of which version of the platform the user has installed, will have the ICO extension.
It should be noted that the ICO file is also used as website icons, which are displayed in the URL bar of a particular browser both before the URL and in the search results. The need to save in ICO format is required while creating icon graphics, ready-made graphic elements, as well as cursors and other icons. Since this type of file can be used as an icon or logo of a web resource, it can be found in the root of the website in the "favicon.ico" section. The browser recognizes such image provided that the file size is 16x16 pixels.
You can open the file in .ico format using any graphic viewer, as well as using software such as IcoFX, ACDSee, Adobe Photoshop, Axialis IconWorkshop, etc.