Support for 16 colors was introduced in Windows 3.0. Icons introduced in Windows 1.0 were 32×32 pixels in size and were monochrome. The ANI file format is used for animated Windows cursors. The only differences between these two file formats are the bytes used to identify them and the addition of a hotspot in the CUR format header the hotspot is defined as the pixel offset (in x,y coordinates) from the top-left corner of the cursor image where the user is actually pointing the mouse.
The CUR file format is an almost identical image file format for non-animated cursors in Microsoft Windows. 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. ICO files contain one or more small images at multiple sizes and color depths, such that they may be scaled appropriately. The ICO file format is an image file format for computer icons in Microsoft Windows.
