How does JPEG compresses images?

[Bean]

Do you know how does JPEG compression works and how it can manage to reduce the size of an image by 10 times and even beyond? Thanks!

 

[mpenza]

it uses fourier transform or something like that to reduce the file sizes.... have forgotten the exact way already.

 

[sehsuan]

try this... http://www.jpeg.org/

 

[Zerstorer]

Generally, it samples the picture in 8x8pixel blocks, applies Discrete Cosine Transform to it, quantizes the DCT values(significant data reduction) and then encodes it into codewords.

Exact specifics should be available on the web if you are really interested.