/prog/ challenge

Did you know it's possible to encode the Y (monochrome detail) and UV (colour) components of a JPEG separately?

^{Examples: http://imgur.com/a/nZFiJ/embed}

Challenge: write a JPEG encoder in your language of choice (the more esoteric, the better) that has that feature.

Bonus points if it's also able to perform other more bizarre manipulations of the JPEG file format. Example: http://i.imgur.com/eJOtn.jpg (looks different in almost every browser)

monochrome detail
It's called LUMINANCE, dad.
It's not for detail. It's a weighted channel created from a source image with deep, intricate colors that a BAKA GAIJIN like you wouldn't understand.