Pixel

           The word pixel is a contraction of the words "picture element" ("pix" is commonly used as a shortcut for "picture"). It is one of the many spots which constitute the representation of a picture in memory or on the screen. Usually these spots are so small and numerous that when they are printed on paper or displayed on the screen one doesn't easily distinguish them from one another and they appear connected so they form a united picture. On your screen there can be 800x600 or 1024x768, etc of them according to the resolution.

          For a black and white picture every pixel is characterizd by its degree of brightness or darkness based on a scale from 0 to 255. In the case of a color picture the color of the pixel is defined by a mixing of 3 basic colors (red, green and blue). The degree of intensity of each of them is also represented by a number between 0 and 255. Thus a pixel with 255 red, 0 green and 0 blue is a red pixel. 255 red, 255 green and 0 blue gives yellow. So it's possible to characterize all shades and hues of a pixel by means of 3 bytes as with the 8 bits of a byte one has 256 possible combinations of 0s and 1s.

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