What is metadata for? The KS3 National Curriculum for Computing requires that you understand how images can be represented by storing numbers that represent the colour of the pixels, but is that all that you need? What would happen if you knew the colours of every pixel in an image, but you didn't know how wide it was? Would you be able to display it correctly? Upload an image and give it a go - the pixels will be displayed in a rectangle, but you choose the width (using the slider at the bottom). Image files store the width and height in their metadata, but here... you are the metadata! NB. If you upload a large image there might be a delay before it is displayed.
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