How JPEG works: Interactively explore JPEG's lossy compression methods

Nicely illustrated, and only one criticism: our preference for luminance (using more bits for "Y" vs "Cr/Cb") isn't due to the number of rods in the eye - there are so many rods so that we can capture more photons at night, and they are usually saturated at daylight illuminances. The effectiveness of the YCbCr encoding is much more related to the predominant pathway to the LGN (80-90% of the "number of bits" used) encoding luminance and center-surround, so those things both map well to using more bits for "Y".

I appreciated the information being presented, but when the controls are not visible at the same time as the thing they effect it makes the interactive component almost worthless.

This has been one of the best explanations I've seen, thanks for sharing