# Image Representation

Images are everywhere on computers and other digital devices, and are one of the main ways we interact with them. Digital devices store everything using digits, so how are these digits used to create the images we see on our computer screens, our smartphones, and our tablets? How do these devices convert a long list of digits into photos, video game graphics, and web pages? This unit will explore how we can represent pictures and colours using binary digits, how these are displayed using pixels on a screen, and why the way we represent these images changes what we see.

We recommend completing Lesson 1 (for the relevant age group) of the Binary Numbers lessons before beginning this unit.

Preparatory knowledge

Students should have completed Lesson 1 (for the relevant age group) of the Binary Numbers topic before beginning this unit.

Images are everywhere on computers and other digital devices. If you think of all the different devices you use, and what you do with them, it is likely that almost all of these will involve a screen or display of some kind! Everything you see on computer screens, whether it is photographs, videos, websites, even text, is an image that a digital device has been programmed to display. Because computers store data as digits, computer images are ultimately represented inside a computer using just 0's and 1's.

Terminology note

In this unit and its lesson plans the word image is used to refer to what is displayed on a computer screen or display at any time. It includes everything seen on a screen, such as videos, websites, apps, …

## Lessons

Ages 5 to 7 Programming challenges
In the teacher observations sections there may also be background notes on the big picture. There is no expectation that 5 to 7 year olds will need to know this, but if you are asked, you have the answer at your fingertips.
1 Colour by numbers No
2 Squeezing pictures into less space No
Ages 8 to 10 Programming challenges
1 Colour by numbers No
2 Squeezing pictures into less space No