| 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. | JPEG is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality. |
| 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). | Image files that employ JPEG compression are commonly called "JPEG files", and are stored in variants of the JIF image format. Most image capture devices (such as digital cameras) that output JPEG are actually creating files in the Exif format, the format that the camera industry has standardized on for metadata interchange. |
| File extension | .ico | .jpg, .jpeg, .jpe, .jif, .jfif, .jfi |
| MIME | image/x-icon, image/vnd.microsoft.icon | image/jpeg |
| Developed by | Microsoft | Joint Photographic Experts Group |
| Type of format | Graphics file format for computer icons | lossy 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, Xara Photo & Graphic Designer. |
| Wiki | https://en.wikipedia.org/wiki/ICO_(file_format) | https://en.wikipedia.org/wiki/JPEG |