img.srcset-missing

InfoSEO audit

Images 640 pixels wide or more (by their width attribute) have no srcset or <picture>, so phones download the full-size file.

What to change

Offer smaller versions with srcset and sizes (srcset="hero-480.jpg 480w, hero-960.jpg 960w" sizes="100vw"), or use the framework's image component (next/image, astro:assets, NuxtImg), which generates them.

The documentation on web.dev

A finding of this rule on a page carries the exact edits for that page: the markup it quotes, and what to write instead.

When it runs

Runs on every SEO audit: of a page, a crawl, a build directory or HTML. Info is a best practice: worth doing, rarely urgent, and --no-info leaves it out. Each finding takes 1 point off the page's score.

The severity here is the rule's usual one: a finding can be raised or lowered when the page gives a reason.

Run it, or skip it

Check a page for this rule alone, after a fix for instance:

npx @rivi-software/agentic-seo-check audit https://example.com --rule img.srcset-missing

Or from an assistant, with the MCP tool seo_audit_page:

{
  "url": "https://example.com",
  "rules": [
    "img.srcset-missing"
  ]
}

To leave it out of an audit, pass --disable img.srcset-missing on the command, or disableRules: ["img.srcset-missing"] to a tool.

All 7 rules