AQA Computer Science GCSE
Data Representation – Representing Images
All data that is used by computers has to be represented using binary numbers. Everything. Including images.
The way in which computers break down images into a grid of pixels and then apply a value to each pixel is actually fairly simple once you get your head around it.
Image Representation Slides – slides from class
Image Representation sheet – textbook style double page spread
Image file definitions – single slide
All the key information is in those documents, but you also need to be able to do calculations, which is the trickier bit.
Image File Calculations slides – simple calculations...
Image File Size summary – a single slide that summarises the file size workings formulae
There is a really annoying question the exam board asks regularly that frequently catches people out:
More complex image file size calculations – this is tricky to get your head around. Just trust it
Some other resources:
Black and white bitmap – for printing by me and cutting up
Image Exam Questions – some quite complex questions here which show what could be done and how this topic relates back to binary and hexadecimal. Your real questions are actually likely to be easier than these...