Icon

What is an Icon in the Computer?

An icon is a small image used to indicate something in the computer screen. computer. There are various kinds of icons. For example:

1. Every application typically has its own icon. Clicking or double-clicking on these icons opens the applications.
2. On smartphones, apps have their icons, and touching them launches the app.
3. Files and folders have their own icons, which identify the type of file or folder that they are.
4. Buttons in a toolbar generally have no text label, and only an icon.
5. Websites have their own icons, also known as favicons, which appears on tabs in web browsers.
6. The cursor of the mouse is an icon.

Image Format

Icons are generally saved in a lossless image format that supports transparency, as there have been many types of icons through history, there have also been many formats used.

The general format for icons is PNG.

There's a Windows icon format, with the file extension .ico, that is used because it saves images of multiple sizes as one file. This means you could have a 16x16px icon and a 32x32px icon in a single file, for example.

Historically, GIF was used for animated icons, as PNG doesn't support animated images natively. BMP could also been used icons, despite not supporting transparency, because some applications displayed the pink color #FF00FF as transparent (called magic pink).

Cursors use a special .cur format which contains the data for which pixel of the image is the hotspot of the mouse pointer, e.g. the typical arrow cursor would have its hotspot at the top-left of the icon, instead of at the center of the icon.