"Google Chrome Blog宣布了新的WebP无损压缩格式以及对透明的支持。据测试，从PNG无损压缩到WebP后，文件大小缩小了45%。和通过pngcrush、pngout处理后的PNG相比，也缩小了28%。除了在无损压缩模式中支持透明外，透明背景的图片也可以保持透明进行有损压缩，这可以在保证一定的图像质量的前提下，极大地缩小文件大小。这里还有一些例子。"

PNG file size: 118.5 KB	WebP-lossy (with alpha) file size: 23.4 KB
"baby tux for my user page" 2
PNG file size: 40.5 KB	WebP-lossy (with alpha) file size: 17.3 KB
"PNG transparency demonstration" 3
PNG file size: 215.8 KB	WebP-lossy (with alpha) file size: 83.2 KB
"Gregor Mendel's 189th Birthday" 4
PNG file size: 63.3 KB	WebP-lossy (with alpha) file size: 24.2 KB
"Transparent compass card for overlays" 5
PNG file size: 127.1 KB	WebP-lossy (with alpha) file size: 67.7 KB