| 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 BMP file format, also known as bitmap image file or device independent bitmap (DIB) file format or simply a bitmap, is a raster graphics image file format used to store bitmap digital images, independently of the display device, especially on Microsoft Windows and OS/2 operating systems. |
| 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). | The bitmap image file consists of fixed-size structures as well as variable-size structures appearing in a predetermined sequence. Many different versions of some of these structures can appear in the file, due to the long evolution of this file format. |
| File extension | .ico | .bmp, .dib |
| MIME | image/x-icon, image/vnd.microsoft.icon | image/bmp, image/x-bmp |
| Developed by | Microsoft | Microsoft |
| Type of format | Graphics file format for computer icons | Raster graphics |
| Associated programs | Axialis IconWorkshop, IcoFX, IconBuilder, Microangelo Toolset, Greenfish Icon Editor Pro, GIMP, ImageMagick, IrfanView, ResEdit. | Microsoft Paint, Adobe Photoshop, Paint Shop Pro, the GIMP, GraphicConverter, Helicon Filter, ImageMagick, Inkscape, IrfanView, Pixel image editor, Paint.NET. |
| Wiki | https://en.wikipedia.org/wiki/ICO_(file_format) | https://en.wikipedia.org/wiki/BMP_file_format |