Speed
Responsive images
Why it matters
Without srcset or <picture>, phones download the same large image files as desktop screens. That wastes mobile data and slows Largest Contentful Paint.
How to fix it
- 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.
Check it with
- 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.
Scoring: a passed check earns its full weight, a warning half and an error none. How the SEO score works