What is a pixel (and a megapixel)?
In one sentence: One tiny coloured square in a digital picture or screen; 12 megapixels means about 12 million of them.
A little more
A pixel is one tiny coloured square in a digital picture or screen. A photo 4000 pixels wide and 3000 tall has 12 million of them, which is what 12 megapixels means. More pixels let you print bigger or zoom in further before squares show.
Megapixels are not the same as megabytes. The file size also depends on how the picture is compressed and how busy it is: a blue sky packs small, a field of grass packs big. To make a photo file much smaller, shrinking its width and height (fewer pixels) usually helps far more than zipping it.
See it in action
- BonusWhy does a video call go blurry when the connection is slow?Dial a pretend video call's bandwidth thinner, spend a tiny 10-bit budget on eyes vs mouth vs wallpaper to still read a facial expression, then reveal the clear face.7 min · interactive
- BonusWhy does zipping photos barely make them smaller?Guess which four suitcase items will squash — a repeating chorus, a letter, a camera photo and TV snow — then pack them with a real (tiny) compressor and see.7 min · interactive
- BonusCan a blocky picture be made sharp again?Guess a mystery blob made of just 16 squares, buy back real patches of detail with five coins, then see the original.7 min · interactive
Do it for real
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