Google's JPEG encoder reduces image size by 35%, could help you save mobile data in the future4
Called Guetzli, which is apparently Swiss German for cookie, the new JPEG encoder does its magic during the so-called quantization stage of image compression, which is when the encoder tries to strike a balance between removing detail to keep size down, without obliterating the source image.
Guetzli uses what Google’s calling a “psychovisual model” to reduce file size, which approximates color perception and “visual masking” more thoroughly than other encoders. This, however, comes at a cost, and in this case that’s time, as Guetzli is decidedly slower than other image compression methods out there.
Check out these examples to get a better idea of how Guetzli works:
As you can see, the new encoder fares better than libjpeg, although, as we said above, it needs more time to produce results.
Here is another example: