# Image Compression

Digital pictures are stored as millions of pixels (megapixels).
In their raw form they can use up a lot of storage space and be very slow to download for viewing online.
But most pictures are converted to a reduced form using clever compression methods that make them much more efficient to store and view online.
In this exercise we’re going to look at one kind of pattern in simple images that computers can use to achieve more efficiency.
The method we’ll look at is called Run-Length Coding, and is the basis of how fax machines work.
Even though fax machines are not so common these days, the method is used now as one of several ways used to keep JPG images small.
And it’s just a fun way to represent a picture as numbers.

## Facilitator preparation

For each slide we’ve written a suggested script, facilitation notes and preparation reminders for you.
<!-- These have been written with the assumption that you are familiar with [the original lesson]('topics:lesson' 'image-representation' 'squeezing-pictures-into-less-space'). -->

### Preparation and teaching resources:

- Read through the [guide on how to deliver CS Unplugged at a distance content]('at_a_distance:delivery-guide').
- Prepare the lesson and practice it in the video conference software that you are going to present with.

### Resources:

- Paper and pen to record first number revealed.

# Image Compression

Digital pictures are stored as millions of pixels (megapixels).
In their raw form they can use up a lot of storage space and be very slow to download for viewing online.
But most pictures are converted to a reduced form using clever compression methods that make them much more efficient to store and view online.
In this exercise we’re going to look at one kind of pattern in simple images that computers can use to achieve more efficiency.
The method we’ll look at is called Run-Length Coding, and is the basis of how fax machines work.
Even though fax machines are not so common these days, the method is used now as one of several ways used to keep JPG images small.
And it’s just a fun way to represent a picture as numbers.

## Facilitator preparation

For each slide we’ve written a suggested script, facilitation notes and preparation reminders for you.
These have been written with the assumption that you are familiar with [the original lesson]('topics:lesson' 'image-representation' 'squeezing-pictures-into-less-space').

### Preparation and teaching resources:

- Read through the [guide on how to deliver CS Unplugged at a distance content]('at_a_distance:delivery-guide').
- Prepare the lesson and practice it in the video conference software that you are going to present with.

### Resources:

- Paper and pen to record first number revealed.

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Add link to new lesson
