Google Guetzli compression algorithm squeezes more out of JPEGs
by from Techreport on (#2G6ZR)
Waiting for images to load is no fun. Neither is paying for bandwidth to serve or receive those images. We've reported in the recent past on Google's efforts to get more detail out of small images and reduce file sizes of images and other web files. The company's Guetzli JPEG encoding algorithm improvement effort looks to have a greater immediate impact because of its ability to potentially reduce image file sizes by up to 35% at the same image quality level when compared to traditional encoders, while maintaining decoding compatibility with existing browsers.
Left: original, center: libjpeg, right: Guetzli. 
Note the reduced artifacting ...