https://blog.wongcw.com/2018/10/06/%e5%9b%be%e4%bb%85%e5%89%a9%e4%b8%8bsafari%e4%ba%86%ef%bc%9afirefox%e5%ae%a3%e5%b8%83%e6%94%af%e6%8c%81%e8%b0%b7%e6%ad%8c%e7%9a%84webp%e5%9b%be%e7%89%87%e6%a0%bc%e5%bc%8f/