Compression Techniques
At Google, we are constantly looking at ways to make web pages load faster. One way to do this is by making web images smaller. Images comprise up to 60%-65% of bytes on most web pages and page size is a major factor in total rendering time. Page size is especially important for mobile devices, where smaller images save both bandwidth and battery life.
WebP is a new image format developed by Google and supported in Chrome, Opera and Android that is optimized to enable faster and smaller images on the Web. WebP images are about 30% smaller in size compared to PNG and JPEG images at equivalent visual quality. In addition, the WebP image format has feature parity with other formats as well. It supports:
Lossy compression: The lossy compression is based on VP8 key frame encoding. VP8 is a video compression format created by On2 Technologies as a successor to the VP6 and VP7 formats.
Transparency: 8-bit alpha channel is useful for graphical images. The Alpha channel can be used along with lossy RGB, a feature that's currently not available with any other format.
