Learn: Data Representation - Images

Welcome!Today we'll learn about how images are represented in computers. It's an important topic for understanding how computers store and display pictures!

What is an image?An image is made up of tiny squares called pixels. Each pixel represents a single colour and together they form the full picture. Computers store images using numbers to represent these colours.

Pixels and resolutionPixels are the smallest elements of an image. Resolution is the number of pixels in width and height. Higher resolution means more pixels, which generally makes the image clearer but increases file size.

Colour depthColour depth refers to the number of bits used to represent the colour of a single pixel. For example, 8-bit colour depth can represent 256 different colours, while 24-bit colour depth can represent millions of colours.

Metadata in imagesMetadata is extra information stored with an image, like its resolution, colour depth, and file format. Metadata helps computers understand how to display the image correctly.

File size calculationTo calculate the file size of an image, use the formula: File size = Colour depth × Image width × Image height. For example, a 24-bit image that is 100 pixels wide and 200 pixels high would have a file size of 24 × 100 × 200 = 480,000 bits.

CompressionCompression reduces the file size of an image. Lossy compression removes some data, reducing quality but saving space. Lossless compression keeps all data, ensuring no quality is lost.

Review Time!Great work! You've learned about pixels, resolution, colour depth, metadata, file size calculation, and compression. Let's test your understanding with a few final questions.