Guetzli
Guetzli is a JPEG encoder that aims to improve the web experience through highly optimized image compression that still yields great image quality. The encoder requires substantially more time than libjpeg but the results have been considered much more impressive in human rated comparisons. Compressed mages are typically 20-30% smaller than images of equivalent quality generated by libjpeg. Guetzli generates only sequential (nonprogressive) JPEGs due to faster decompression speeds they offer.
