| Format introduction | The ICO file format is an image file format for computer icons in Microsoft Windows. ICO files contain one or more small images at multiple sizes and color depths, such that they may be scaled appropriately. In Windows, all executables that display an icon to the user, on the desktop, in the Start Menu, or in Windows Explorer, must carry the icon in ICO format. | The Graphics Interchange Format (better known by its acronym GIF) is a bitmap image format that was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability. |
| Technical details | An ICO file is made up of an ICONDIR ("Icon directory") structure, containing an ICONDIRENTRY structure for each image in the file, followed by a contiguous block of all image bitmap data (which may be in either Windows BMP format, excluding the BITMAPFILEHEADER structure, or in PNG format, stored in its entirety). | GIF supports up to 8 bits per pixel for each image, allowing a single image to reference its own palette of up to 256 different colors chosen from the 24-bit RGB color space. GIF images are compressed using the Lempel-Ziv-Welch (LZW) lossless data compression technique to reduce the file size without degrading the visual quality. |
| File extension | .ico | .gif |
| MIME | image/x-icon, image/vnd.microsoft.icon | image/gif |
| Developed by | Microsoft | CompuServe |
| Type of format | Graphics file format for computer icons | lossless bitmap image format |
| Associated programs | Axialis IconWorkshop, IcoFX, IconBuilder, Microangelo Toolset, Greenfish Icon Editor Pro, GIMP, ImageMagick, IrfanView, ResEdit. | Apple Safari, Google Chrome, Mozilla Firefox, Internet Explorer, Adobe Photoshop, Paint Shop Pro, the GIMP, ImageMagick, IrfanView, Pixel image editor, Paint.NET. |
| Wiki | https://en.wikipedia.org/wiki/ICO_(file_format) | https://en.wikipedia.org/wiki/GIF |