seo-images skill

Image Optimization Analysis

Checks

Alt Text

• Present on all elements (except decorative: role="presentation")
• Descriptive: describes the image content, not "image.jpg" or "photo"
• Includes relevant keywords where natural, not keyword-stuffed
• Length: 10-125 characters

Good examples:

• "Professional plumber repairing kitchen sink faucet"
• "Red 2024 Toyota Camry sedan front view"
• "Team meeting in modern office conference room"

Bad examples:

• "image.jpg" (filename, not description)
• "plumber plumbing plumber services" (keyword stuffing)
• "Click here" (not descriptive)

File Size

Tiered thresholds by image category:

Recommend compression to target thresholds where possible without quality loss.

Format

Recommend WebP/AVIF over JPEG/PNG. Check for element with format fallbacks.

Recommended Element Pattern

Use progressive enhancement with the most efficient format first:

<picture>
  <source srcset="image.avif" type="image/avif">
  <source srcset="image.webp" type="image/webp">
  <img src="image.jpg" alt="Descriptive alt text" width="800" height="600" loading="lazy" decoding="async">
</picture>

The browser will use the first supported format. Current browser support: AVIF 93.8%, WebP 95.3%.

JPEG XL: Emerging Format

Third-party reporting and Wikipedia describe a Rust-based JPEG XL decoder as shipped in Chrome 145 stable (2026-02-10) behind the chrome://flags/#enable-jxl-image-format flag, not enabled by default; no Google-owned confirmation was retrieved in the fact pack. Because default support is not confirmed, it is not yet practical for production web delivery. Keep serving AVIF/WebP with JPEG fallback and monitor.

Responsive Images

• srcset attribute for multiple sizes
• sizes attribute matching layout breakpoints
• Appropriate resolution for device pixel ratios

<img
  src="image-800.jpg"
  srcset="image-400.jpg 400w, image-800.jpg 800w, image-1200.jpg 1200w"
  sizes="(max-width: 600px) 400px, (max-width: 1200px) 800px, 1200px"
  alt="Description"
>

Lazy Loading

• loading="lazy" on below-fold images
• Do NOT lazy-load above-fold/hero images (hurts LCP)
• Check for native vs JavaScript-based lazy loading

<!-- Below fold - lazy load -->
<img src="photo.jpg" loading="lazy" alt="Description">

<!-- Above fold - eager load (default) -->
<img src="hero.jpg" alt="Hero image">

Detected lazy-loader methods (lazy_method field)

"${CLAUDEPLUGINROOT}/scripts/claude-seo" run parsehtml.py classifies each image's lazy-loading mechanism via the lazymethod field on every image entry. Five values:

When auditing image SEO, report lazy_method alongside loading so users know whether their site is using a JS-driven lazy-loader (in which case the native loading="lazy" attribute is intentionally absent, that is not a regression).

fetchpriority="high" for LCP Images

Add fetchpriority="high" to your hero/LCP image to prioritize its download in the browser's network queue:

<img src="hero.webp" fetchpriority="high" alt="Hero image description" width="1200" height="630">

Critical: Do NOT lazy-load above-the-fold/LCP images. Using loading="lazy" on LCP images directly harms LCP scores. Reserve loading="lazy" for below-the-fold images only.

decoding="async" for Non-LCP Images

Add decoding="async" to non-LCP images to prevent image decoding from blocking the main thread:

<img src="photo.webp" alt="Description" width="600" height="400" loading="lazy" decoding="async">

CLS Prevention

• width and height attributes set on all elements
• aspect-ratio CSS as alternative
• Flag images without dimensions

<!-- Good - dimensions set -->
<img src="photo.jpg" width="800" height="600" alt="Description">

<!-- Good - CSS aspect ratio -->
<img src="photo.jpg" style="aspect-ratio: 4/3" alt="Description">

<!-- Bad - no dimensions -->
<img src="photo.jpg" alt="Description">

File Names

• Descriptive: blue-running-shoes.webp not IMG_1234.jpg
• Hyphenated, lowercase, no special characters
• Include relevant keywords

CDN Usage

• Check if images served from CDN (different domain, CDN headers)
• Recommend CDN for image-heavy sites
• Check for edge caching headers

Output

Image Audit Summary

Prioritized Optimization List

Sorted by file size impact (largest savings first):

Recommendations

1. Convert X images to WebP format (est. XX KB savings)
2. Add alt text to X images
3. Add dimensions to X images
4. Enable lazy loading on X below-fold images
5. Compress X oversized images

Image SERP Analysis

When DataForSEO MCP is available, enhance the image audit with competitive data.

/seo images serp

Cross-reference on-page images with the image results visible in the Google SERP.

Workflow:

Use the images element of serporganiclive_advanced (depth=100) when the SERP has one, and say plainly when no image SERP data is available

1. The pinned DataForSEO MCP server (2.8.10) has no Google Images SERP tool.

1. Extract: top domains, image types, alt text patterns
2. Output competitor image SERP landscape

Output:

Analysis includes:

• Domain dominance: which sites own the most image positions (top 10 by count)
• Alt text patterns: common title/alt patterns in top-ranking images
• Format distribution: WebP vs JPEG vs PNG in top results
• Opportunity score: keywords where you have page rankings but no image presence

If DataForSEO MCP is not available, inform user and suggest installing the extension.