Computer graphics refers to drawing pictures on a computer screen. There are two main types: raster graphics, which uses pixels to build images, and vector graphics, which uses mathematical formulas to define shapes. Key developments in computer graphics history include early programs in the 1950s and 1960s, Ivan Sutherland's Sketchpad program in 1963, and Pixar's use of CGI in the 1995 film Toy Story. Computer graphics is now used widely in areas like design, movies, games, medical imaging, and scientific visualization.