Google wants to outdo .Jpeg

Google is trimming down the size of image files in a bid to make the internet faster.

In a blog it announced that it’s releasing a developer preview of a new image format, which it has dubbed WebP. This is an alternative to the JPEG format, which is typically used today for web pictures and images. According to the search giant WebP should “significantly” reduce the byte size of images. It hopes this reduction will help sites load faster.

Richard Rabbat, a Google product manager, wrote in a blog post: “Images and photos make up about 65 percent of the bytes transmitted per web page today. They can significantly slow down a user’s web experience, especially on bandwidth-constrained networks such as a mobile network.

“Images on the web consist primarily of lossy formats such as JPEG, and to a lesser extent lossless formats such as PNG and GIF. Our team focused on improving compression of the lossy images, which constitute the larger percentage of images on the web today.”

It said to improve on the compression that JPEG provides, it used an image compressor based on the VP8 codec that Google open-sourced in May 2010. It applied the techniques from VP8 video intra frame coding to push the envelope in still image coding as well as adapting a very lightweight container based on RIFF.

“While this container format contributes a minimal overhead of only 20 bytes per image, it is extensible to allow authors to save meta-data they would like to store,” it added.

Google claims: “In order to gauge the effectiveness of our efforts, we randomly picked about 1,000,000 images from the web (mostly JPEGs and some PNGs and GIFs) and re-encoded them to WebP without perceptibly compromising visual quality. This resulted in an average 39 percent reduction in file size.

“We expect that developers will achieve in practice even better file size reduction with WebP when starting from an uncompressed image.”