## 使用 PNG 對圖片失真壓縮...

PNG 是無失真影像壓縮格式，但我們仍然可以修改 pixel (失真) 讓 PNG 壓縮率更好。今天在「PNG can be a lossy format」看到的 Mac OS X 應用程式就是這個用途。

GIF has antiquated compression and it's a complete waste of bandwidth. Even lossy GIF is worse than lossless optimized PNG.

Whether lossy PNG gives better results than JPEG depends on the image. JPEG often gives smaller files, except when image has sharp edges (e.g. text) or any transparency (which JPEG does not support at all).

Optimized lossy PNG is still a bit larger than lossy JPEG-XR/WebP/JPEG-2K, but unlike these formats it's supported by all browsers and operating systems without any fuss or hacks.