Computer icons are incorporated into any graphical user interface. Icons are small pictograms of standard sizes that depict objects, actions, and symbols. In graphical user interfaces, icons are used as a faster, more intuitive way to communicate with the user. Icons depicting standard elements of a user interface are more visually appealing than text, can be recognized faster, and are certainly easier on the eyes.
Originally developed in 1970 by the Xerox Research Center and widely popularized by the Mac OS and Microsoft Windows platforms, icons make new users feel more comfortable with computer systems, learn faster and interact more efficiently. Icons can be used to replace or supplement text commands. Commonly used in menus, toolbars, on buttons and in the latest ribbon-style user interfaces, icons have come a long way from the original concept.
There are multiple image formats for storing icons. The Windows systems use Windows icons in the platform-specific ICO format. Mac OS computers use 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 Mac OS systems, while Unix users can create their icons with just about any image editor.
Generally speaking, icons are square pictures that come in a number of standard sizes and color resolutions. Most systems use icons of 16×16 to 128×128 pixels, while some platforms readily accept icon images as large as 512×512 pixels. The ultra-high definition 512×512 pixel icons were first employed in Mac OS Leopard.
Pixel dimensions of all icons are platform dependent. For example, Windows icons are defined as images in 16 and 256-color gammas as well as True Color images with alpha channel. Windows icons are supplied in standard resolutions of 16×16, 32×32, and 48×48 pixels. Windows Vista defines new standards for Windows icons, including icons in resolutions of up to 256×256 pixels in True Color only. Optionally, icons of 128×128 and 512×512 pixels are supported. Interestingly, the higher resolution versions of Windows Vista icons are stored in compressed PNG format instead of Windows ICO used in previous versions of Windows and for lower resolution images. Other platforms such as Windows Mobile can use standard icons of other sizes, e.g. 24×24 pixels.
Numerous independent designers are providing custom icons. Aha-Soft offers a variety of Windows icons, Mac icons, and PNG icons in all sizes and resolutions standard to those platforms. The company provides royalty-free icons individually and in matching sets that include icons drawn a common style or theme.