In case it (somehow) isn’t obvious, Google cares a lot about reducing the size of webpages, and the images on those webpages. On one hand, smaller webpages and images means that both of those things will download quicker, and at the same time, it means that the hosting provider isn’t pushing more bandwidth than it needs to (that can get expensive).
Years ago, Google unveiled WebP, an image format for both lossy and lossless compression. According to the company, it cuts down comparable images by at least 10%. The problem at this point, though, is that while WebP can be used in modern browsers, the lack of support for the format in desktop or mobile applications, either for simple viewing or editing, makes it a bit of a chore to have to encounter (sorry, Google).
That’s why the company’s new Guetzli algorithm for trimming JPGs down is so interesting: it manages to shave precious kilobytes off without requiring a new image format. Effectively, your 100KB image could become 70KB without any perceivable quality loss. Take a look at this example:
On the left is an uncompressed image, which is evident due to the absolute lack of artifacts. In the middle is the image compressed with libjpeg, and finally, the third is the same image compressed with Guetzli (which is “cookie” in German, by the way) . With libjpeg, there’s some very noticeable (at least in this close-up) “ringing” occurring around the line in the center, while the effect is mild with Guetzli. Here’s another example involving a cat’s eye:
According to Google, users it’s surveyed prefer Guetzli-produced images overall, but this example does show one of its shortcomings. While libjpeg retains the green-ish glimmer on the cat’s eye here, it becomes a faded purple (or perhaps gray) in the Guetzli image. Beyond that, though, the ringing effect is again more pronounced on the libjpeg-processed image. The tradeoff in this case could be worth it, because a detail such as eye glimmer is not likely to be noticed without zooming in.
Google doesn’t say when people will get to play around with Geutzli, but the company has big plans for its future. “It is our hope that webmasters and graphic designers will find Guetzli useful and apply it to their photographic content, making users’ experience smoother on image-heavy websites in addition to reducing load times and bandwidth costs for mobile users.”
As a site that cares a lot about page-loads and image sizes (there’s a reason an image like this is 44KB, not 105KB), we at Techgage look forward to being able to give this algorithm a good test.