In digital imaging, a pixel, pel, or picture element is the smallest addressable element in a raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, pixels are the smallest element that can be manipulated through software.
A photograph of subpixel display elements on a laptop's LCD screen
Pixel art
Geometry of color elements of various CRT and LCD displays; phosphor dots in the color display of CRTs (top row) bear no relation to pixels or subpixels.
Samsung UA40M5860AKCHD TV subpixels
The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue.
Full color image along with its R, G, and B components
The first permanent color photograph, taken by Thomas Sutton in 1861 using James Clerk Maxwell's proposed method of three filters, specifically red, green, and violet-blue
A photograph of Mohammed Alim Khan (1880–1944), Emir of Bukhara, taken in 1911 by Sergey Prokudin-Gorsky using three exposures with blue, green, and red filters
RGB phosphor dots in a CRT monitor