Images

• Images stored as


  series of pixels
• Bitmap images


  made up of pixels
• colour of each pixel represented by

  binary code
• number of colour is related to

  number of bits the code has
• black and white images

  only uses 2 colour

  need 1 bit for each pixel
• binary values for 2 bit image with 4 colours

  00, 01, 10, 11
• How to get greater range of colours

  increase number of bits
• colour depth

  number of bits used for each pixel
• bit depth most devices use

  24 bit colour depth

  8 bits for the levels of red, green and blue in each pixel

  produce around 10 million colours
• What happens when great image resolution or colour depth is used?

  more bits in image

  higher quality image

  increases file size
• Metadata

  information stored in an image file which is used to recreate the image on screen from binary data to each pixel
• Examples of Metadata

  file format

  height

  width

  colour depth

  resolution