Computer Icon

On computer displays, a computer icon (or simply an icon) is a small pictogram. Icons have been used to supplement the normal alphanumerics of the computer. Modern computers now can handle bitmapped graphics on the display terminal, so the icons are widely used to assist users.

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.

A computer icon usually ranges from 16 by 16 pixels up to 128 by 128 pixels. Some operating systems feature icons up to 512 by 512 pixels. When the graphical output device has a smaller size, the icon size is small. Vision-impaired users (due to such conditions as poor lighting, tired eyes, medical impairments, bright backgrounds, or color blindness) may need to utilize the self-selected icon size options.

Source : Wikipedia