The file extension ANI marks so-called Microsoft Windows animated cursor files, ie animated cursors or mouse pointer files. Ani files are similar to cur files in Ico format. However, while cur files contain only one image, the ANI file contains several images that can be played back as an animation. In addition, you also include information about the author, frame rate and playing time. The rotating hourglass or the circle with rotating gradient (as of Vista) are such ANI files.
The ANI format was introduced with Windows 95, then expanded in later Windows version to allow also multicolored cursors. However, many cursor files still have the cur format. Even under Windows 7 cur files are still used.
Directly under Windows, ANI files can not be opened without a corresponding editor. In order to assign an ANI file to a specific mouse pointer state, you have to go to the control panel under Display on the mouse pointer properties. Under the tab pointer you will find a whole series of ready-made topics that access different ANI files.
Own ANI files are assigned by selecting the appropriate state and clicking on Browse. (do not forget to save the new theme) Ani themes can also be part of a whole desktop theme.
To create ANI files yourself or to view or change existing ones, there are various graphics programs, but also special editors.
It should be noted that Microsoft announced on 31/07/2007 security vulnerability of ANI files. The problem is Windows 2000 to Vista. A security fix for Windows (Microsoft Security Bulletin MS07-017; KB 925902) resolves this issue.