Smaller JPEGs, better quality?

26 March 2017

Google's new JPEG encoder promises smaller file sizes and better image quality.

Google has released a new JPEG encoder that it says can reduce file size by up to 35% with minimal loss of image detail and quality. Google says the open source Guetzli encoder "can enable faster online experiences by producing smaller JPEG files while still maintaining compatibility with existing browsers, image processing applications and the JPEG standard".

A 20 x 24 pixel zoomed area from a picture of a cat’s eye. Uncompressed original (left), libjpeg compression (middle), Guetzli compression (right). – Source: Google.
A 20 x 24 pixel zoomed area from a picture of a cat’s eye. Uncompressed original (left), libjpeg compression (middle), Guetzli compression (right). – Source: Google.

On the downside, while Guetzli creates smaller image file sizes, the process of compressing files is apparently "significantly longer" than currently available methods.

In a press release announcing Guetzli, Google claims it is a worthy trade-off with its own tests showing "human raters consistently preferred the images Guetzli produced over libjpeg images, even when the libjpeg files were the same size or even slightly larger".

It may be some time before photographers see the benefits of the new compression algorithm with Guetzli currently only available in code form.