What Are Icons?
Computer icons are an integral part of any modern GUI. Icons are small pictograms of standardized resolutions that visually represent objects, actions, and symbols. In window-based systems, icons are used as a faster, more intuitive way to communicate with the user. Icons representing standard elements of a user interface are better visible than text, can be recognized faster, and are easier for new computer users.
Originally developed in 1970 by the Xerox Research Center and widely popularized by the Apple Macintosh and Microsoft Windows platforms, icons make computer novices feel more comfortable with operating systems, learn faster and interact more efficiently. Icons can be employed to replace or supplement text commands. Widely used in menus, toolbars, on buttons and in the latest ribbon-type user interfaces, icons have come a long way from the original concept.
There are several image formats for storing icons. Microsoft Windows systems store Windows icons in the platform-dependent ICO format. Mac OS computers store Mac icons in their specific formats, while Unix-based systems employ PNG icons for most applications. As such, icon software is generally available for the Windows and Apple systems, while Unix users can create PNG icons with just about any graphic editor.
Generally speaking, icons are square images that come in a number of standard sizes and color resolutions. Most systems use icons of 16x16 to 128x128 pixels, while some platforms readily accept icons as large as 512x512 pixels. The big 512x512 pixel icons were first used in Mac OS Leopard.
Pixel resolutions of all icons are operating system dependent. For example, Windows icons are defined as pictures in 16 and 256-color gammas as well as True Color pictures with alpha channel. Windows icons are supplied in standard resolutions of 16x16, 32x32, and 48x48 pixels. Windows Vista implements new standards for Windows icons, including icons in sizes of up to 256x256 pixels in True Color only. Optionally, icons of 128x128 and 512x512 pixels are supported. Interestingly, the higher resolution versions of Windows Vista icons are stored in compressed PNG format instead of Windows ICO used in older versions of Windows and for lower resolution icons. Other platforms such as Windows Mobile can use standard icons of other sizes, such as 24x24 pixels.
Numerous independent designers are offering custom icons. OrderIcon offers a variety of Windows icons, Mac icons, and PNG icons in all sizes and resolutions common to those platforms. The company provides royalty-free icons individually and in matching sets incorporating icons drawn a common style or theme.