速度
响应式图片
为何重要
Without srcset or <picture>, phones download the same large image files as desktop screens. That wastes mobile data and slows Largest Contentful Paint.
如何修复
- Generate several sizes of each image and list them in srcset with a sizes attribute.
- Most CMSs (WordPress, Shopify) do this automatically if images are inserted through the media library.
使用以下工具检查
- Image Alt Text Checker – Find images with missing alt text, missing dimensions and no lazy loading.
- Page Size Checker – Find the total weight of a page and which images, scripts and styles are heaviest.
评分：通过的检查获得全部权重，警告获得一半，错误则不得分。 SEO 评分如何运作