Representing Images

• Images can be stored in binary as bitmaps or vectors
• Bitmap pictures are constructed from coloured squares called pixels
• Vector pictures store the mathematics to draw coloured shapes
• Each pixel of a bitmap is stored in binary
• The number of bits required for each pixel depends on the number of colours required
• 1 bit can store 2 colours: black or white
• 2 bits can store 4 colours
• The number of colours can be calculated as 2^n, where n is the number of bits for each pixel
• The number of bits for each pixel is known as the colour depth
• Metadata is additional data stored with the image to define the width, height, colour depth and colour palette
• The greater the colour depth and resolution, the larger the file size of the image
• Photographs are stored in 24 bit colour depth, which is over 16 million colours
• This represents the number of different colours the human eye can see