Best SEO Checklist
ONE FOCUSED ACTION

Implement responsive srcset with fallback formats for all images.

DuckDuckGo SEO · Image SEO · Landing-page SEO · Website performance SEO

1 checklist items

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    Why this matters

    Delivering appropriately sized images with modern formats and fallbacks improves loading speed, mobile performance, and image SEO visibility.

    A STARTING-POINT EXAMPLE

    Hypothetical standard operating procedure

    Adapt this example to your site, access, tools, and change process. It is our suggested procedure, informed by the sources below.

    1. Audit current images to identify those lacking srcset or fallback formats.
    2. Generate multiple image sizes optimized for common breakpoints and device pixel ratios.
    3. Create srcset attributes referencing these sizes and include type-based fallback sources for WebP, AVIF, and JPEG/PNG.
    4. Update HTML markup or CMS templates to embed responsive srcset with correct width, height, and aspect-ratio attributes.
    5. Test pages on desktop and mobile devices to confirm appropriate images load and no layout shifts occur on load.

    Watch for

    Serving large or camera-resolution images without resizing harms page speed and user experience, especially on mobile.

    Definition of done

    Images load with device-appropriate sizes and formats, verified by inspecting srcset attributes and network requests in browser dev tools showing WebP/AVIF with fallback.

    Sources & attribution

    1. The Complete Checklist for Image SEO ↗
    2. Image SEO: The Checklist That Wins Visibility and Speed ↗
    3. DuckDuckGo SEO Audit Checklist for Technical and On-Page Fixes ↗
    4. Landing Page Audit Tool ↗
    5. Website Audit Checklist ↗
    6. Image SEO Best Practices - Alt Text Studio ↗
    7. WordPress SEO Checklist for Publishers: On-Page and Technical Basics ↗
    8. Multilingual SEO checklist: What to verify before launch | SimpleLocalize ↗

    Original checklist wording and example SOP by Best SEO Checklist, using source-grounded AI assistance. Editorial contact: Ted Kubaitis, @tedkubaitis on Teams. Check current source guidance before implementation.