Responsive Images Missing srcset or sizes Attributes
Images are served without srcset or sizes attributes, forcing browsers to download full-size images regardless of the viewport. This wastes bandwidth on mobile and smaller screens.
Use this article when
- You need deeper remediation guidance than the issue card can show.
- You want CMS-specific steps before handing the fix to a developer.
- You want a repeatable re-check path after shipping the change.
What this issue is
Images are served without srcset or sizes attributes, forcing browsers to download full-size images regardless of the viewport. This wastes bandwidth on mobile and smaller screens.
Why it matters
Images are served without srcset or sizes attributes, forcing browsers to download full-size images regardless of the viewport. This wastes bandwidth on mobile and smaller screens. This affects load speed, Core Web Vitals, and how many visitors stay long enough to convert.
How we detect it
- FreeSiteAudit flags this issue when the rule for CWV-SRCSET-SIZES-001 fails and the page evidence points to Dom body.
- You can usually confirm this by checking the page source or the relevant page settings inside your CMS.
Evidence examples
How to fix it
- 1Add srcset with multiple image widths for each <img> element
- 2Include a sizes attribute that describes the image layout width at each breakpoint
- 3Use an image CDN that auto-generates srcset variants
How to re-check it
- Inspect key images in DevTools and confirm srcset and sizes attributes are present
Related tools
This issue is best verified with the full FreeSiteAudit crawl rather than a single-point mini tool.