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Icon (computing)

A computer icon is a small graphic, usually ranging from 16 pixels by 16 pixels to upto 128 pixels by 128 pixels, which represents a file, folder, application or device on a computer system. Icons were first developed as a tool for making computer interfaces easier for novices to grasp in the 1970s at the Xerox Palo Alto Research Center facility. Icon-driven interfaces were later popularized by the Apple Macintosh and Microsoft Windows operating environments.

Icons may also be found on the toolbars and in the menus of programs such as Microsoft Word.

Virtually every major computer operating system now uses icon-based GUIs to display information to end users.

Function or program icons

Most computer functions in a Graphic User Interface (GUI) are represented by a function icon. Placing the cursor on the icon, and clicking a mouse (or trackball or other) button usually starts the function or program.

The creation of a good function icon can be considered as an art form in itself, comparable to that practiced in the past in the domain of miniature painting by old masters such as Joseph Severn and Charles-Francois Daubigny.

The icon must be original, distinctive, and tiny and it must be useful on a wide variety of monitors set at different resolutions. This work is further complicated by the need to create several sets of function icons for several types of views in several types of operating systems, for any given program. For instance, the GUI guidelines in one operating system might specify the need to create sets of 16, 32, and 48 pixel icons for any program while the GUI guidelines in another system might specify sets of 16, 24, 48 and 96 pixel icons for any program.

Document icons

In certain views of folders or directories in a Graphic User Interface (GUI) all the documents or files are represented as icons, in addition to their file name and, in certain cases, other details. In most systems and for most files these icons are generic images, representing the program used to create the file, or the file type. In this case, the comments made in the previous paragraph concerning the icon as an art form also apply to file icons.

In the case of graphic files most modern systems replace the generic icon with a reduced image of the graphic. This reduced image usually fits into a 128 by 128 or a 117 by 117 pixel box, depending on the operating system used. It is available in a "thumbnail view" or within some other specialized viewing area on the screen.

The most recent systems and the most recent applications often generate such reduced images from other types of files in programs which have not been traditionally viewed as "graphic", such as word processor software or business presentation programs such as Agnubis, Impress, or PowerPoint.