
Image Optimization Analysis
FreeEnhance SEO and performance through image audits.
Free · Opens the source repo
What Image Optimization Analysis does
Image Optimization Analysis is a skill designed for developers and web designers focused on improving the SEO and performance of images on their websites. This tool conducts a comprehensive audit of images, checking critical factors such as alt text, file sizes, formats, responsive images, lazy loading practices, and more. By utilizing this skill, users can ensure that their images are not only visually appealing but also optimized for search engines and user experience.
The skill evaluates the presence and quality of alt text, ensuring that all images are described appropriately and include relevant keywords without falling into keyword stuffing. It also assesses file sizes against recommended thresholds for different image categories, providing guidance on how to compress images without sacrificing quality. Furthermore, it analyzes image formats, recommending modern formats like WebP and AVIF for better compression and browser compatibility, while also checking for the correct implementation of the <picture> element for fallback support.
In addition to these checks, the skill provides insights into responsive image handling, lazy loading practices, and measures to prevent cumulative layout shift (CLS). By ensuring that images are properly sized and lazy loaded only when appropriate, users can enhance their website's performance metrics, which are crucial for SEO rankings. The skill also emphasizes the importance of descriptive file names and CDN usage to further optimize image delivery.
Overall, Image Optimization Analysis is a valuable tool for anyone looking to improve their website's image SEO and performance, making it essential for web developers and designers aiming to create fast, efficient, and search-friendly websites.
When to use it
Use this skill when conducting an image audit or when optimizing images for better SEO and performance on a website.
When not to use it
This skill may not be suitable for users who do not manage image-heavy websites or require simple image editing tools.
What you can build with it
Conducting an Image Audit
Use this skill to perform a thorough analysis of all images on a website, identifying areas for optimization.
Improving SEO Rankings
Leverage the insights from this skill to enhance image SEO, leading to better search engine rankings.
Optimizing for Performance
Utilize the skill to ensure images are optimized for performance, reducing load times and improving user experience.
How to install Image Optimization Analysis
View source1. Install with the skills CLI
npx skills add agricidaniel/claude-seo/seo-images --agent claude-code2. Or install it manually
Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.
Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs
Inside SKILL.md
Written by agricidanielImage Optimization Analysis
Checks
Alt Text
- Present on all
<img>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:
| Image Category | Target | Warning | Critical |
|---|---|---|---|
| Thumbnails | < 50KB | > 100KB | > 200KB |
| Content images | < 100KB | > 200KB | > 500KB |
| Hero/banner images | < 200KB | > 300KB | > 700KB |
Recommend compression to target thresholds where possible without quality loss.
Format
| Format | Browser Support | Use Case |
|---|---|---|
| WebP | 97%+ | Default recommendation |
| AVIF | 92%+ | Best compression, newer |
| JPEG | 100% | Fallback for photos |
| PNG | 100% | Graphics with transparency |
| SVG | 100% | Icons, logos, illustrations |
Recommend WebP/AVIF over JPEG/PNG. Check for <picture> element with format fallbacks.
Recommended <picture> 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
srcsetattribute for multiple sizessizesattribute 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)
scripts/parse_html.py classifies each image's lazy-loading mechanism via the
lazy_method field on every image entry. Five values:
lazy_method | Signal detected | Common stack |
|---|---|---|
native | loading="lazy" HTML attribute | Modern browsers, plain HTML |
perfmatters | data-perfmatters-src/-srcset OR class perfmatters-lazy | WordPress + Perfmatters plugin |
ewww | data-ewww-src / data-eio OR class lazyload-eio | WordPress + EWWW Image Optimizer |
js-generic | data-src / data-lazy-src / data-original / data-srcset OR class lazyload/lazyloaded/lazy | Lazysizes, vanilla-lazyload, jQuery plugins |
none | Neither attribute nor class signal | Page is not lazy-loading this image |
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
widthandheightattributes set on all<img>elementsaspect-ratioCSS 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.webpnotIMG_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
| Metric | Status | Count |
|---|---|---|
| Total Images | - | XX |
| Missing Alt Text | ❌ | XX |
| Oversized (>200KB) | ⚠️ | XX |
| Wrong Format | ⚠️ | XX |
| No Dimensions | ⚠️ | XX |
| Not Lazy Loaded | ⚠️ | XX |
Prioritized Optimization List
Sorted by file size impact (largest savings first):
| Image | Current Size | Format | Issues | Est. Savings |
|---|---|---|---|---|
| ... | ... | ... | ... | ... |
Recommendations
- Convert X images to WebP format (est. XX KB savings)
- Add alt text to X images
- Add dimensions to X images
- Enable lazy loading on X below-fold images
- Compress X oversized images
Image SERP Analysis
When DataForSEO MCP is available, enhance the image audit with competitive data.
/seo images serp <keyword>
Cross-reference on-page images with Google Images SERP rankings.
Workflow:
- Fetch Google Images results via
serp_google_images_live_advanced(depth=100) - Extract: top domains, image types, alt text patterns
- Output competitor image SERP landscape
Output:
| Rank | Domain | Title/Alt | Image URL | Page URL |
|---|---|---|---|---|
| 1 | example.com | "Blue running shoes..." | .../shoes.webp | /products/... |
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.
Image File Optimization
Optimize image files for SEO: format conversion, metadata injection, compression.
/seo images optimize <path>
Optimize image file(s) for web and SEO. Converts to WebP/AVIF, injects IPTC metadata, compresses, and generates responsive variants.
Tools used (in order of preference):
exiftool-- EXIF/IPTC/XMP read/write (install:sudo apt install libimage-exiftool-perl)cwebp-- WebP conversion (install:sudo apt install webp)- ImageMagick
convert-- Format conversion, resizing (pre-installed on most systems) - FFmpeg -- Fallback for format conversion (pre-installed)
Before running: Check which tools are available with which exiftool cwebp convert ffmpeg.
Format Conversion
Convert images to modern formats with metadata preservation:
# WebP (recommended default) - with metadata preserved
cwebp -q 82 -metadata all input.jpg -o output.webp
# WebP via ImageMagick (fallback if cwebp not installed)
convert input.jpg -quality 82 output.webp
# AVIF via FFmpeg (slower encode, best compression)
ffmpeg -i input.jpg -c:v libaom-av1 -crf 30 -still-picture 1 output.avif
# Responsive variants (400w, 800w, 1200w)
convert input.jpg -resize 400x -quality 82 image-400.webp
convert input.jpg -resize 800x -quality 82 image-800.webp
convert input.jpg -resize 1200x -quality 82 image-1200.webp
Metadata Injection (IPTC for Google Images Display)
Google Images displays IPTC Creator, Credit Line, and Copyright in search results. This is NOT a ranking factor but can improve Google Images display and brand attribution.
With exiftool (preferred):
# Read all metadata
exiftool image.jpg
# Inject IPTC + XMP metadata for Google Images rich results
exiftool \
-IPTC:ObjectName="Product Photo Description" \
-IPTC:Caption-Abstract="Detailed image description" \
-IPTC:By-line="Brand Name Photography" \
-IPTC:Credit="Brand Name" \
-IPTC:CopyrightNotice="Copyright 2026 Brand Name" \
-IPTC:Source="brandname.com" \
-XMP:Title="Product Photo Description" \
-XMP:Description="Detailed image description" \
-XMP:Creator="Brand Name Photography" \
-XMP:Rights="Copyright 2026 Brand Name" \
image.jpg
# Batch inject to all images in directory
exiftool -overwrite_original \
-IPTC:By-line="Brand Name" \
-IPTC:CopyrightNotice="Copyright 2026 Brand Name" \
*.jpg *.webp *.png
With ImageMagick (fallback):
identify -verbose image.jpg | head -50
convert input.jpg \
-set comment "Product Photo Description" \
-set IPTC:2:80 "Brand Name Photography" \
-set IPTC:2:116 "Copyright 2026 Brand Name" \
output.jpg
Note: WebP supports EXIF and XMP but not IPTC natively. For WebP files, use XMP fields instead of IPTC. exiftool handles this conversion automatically.
AI-Generated Images: DigitalSourceType (Merchant Center requirement)
For product images produced by generative AI, Google Merchant Center requires
IPTC DigitalSourceType: TrainedAlgorithmicMedia metadata. This is an
operational policy requirement, not a ranking factor: feeds missing this label
on AI-generated imagery can be disapproved.
Primary source (Merchant Center AI-generated content policy): https://support.google.com/merchants/answer/14743464 (the ai-optimization-guide does not document DigitalSourceType/IPTC/Merchant labeling.)
Audit command:
# Audit a directory for the IPTC label (counts: missing, ai, captured, etc.)
claude-seo run iptc_ai_label.py audit ./images/ --json
# Audit a single image
claude-seo run iptc_ai_label.py audit ./hero.webp --json
# Inject the AI label into an image
claude-seo run iptc_ai_label.py inject ./ai-hero.webp \
--source-type trainedAlgorithmicMedia
# Other vocabulary values:
# compositeSynthetic (mix of captured + AI elements)
# algorithmicMedia (created purely by algorithm, NOT from sampled training data)
# compositeWithTrainedAlgorithmicMedia (e.g. AI inpainting/outpainting over real media)
# digitalCapture (fully captured photograph)
Raw exiftool equivalents (for ad-hoc usage):
# Inject manually
exiftool \
-XMP-iptcExt:DigitalSourceType="https://cv.iptc.org/newscodes/digitalsourcetype/trainedAlgorithmicMedia" \
ai-generated-product.jpg
# Audit: find images missing the label across a directory
exiftool -if 'not $XMP-iptcExt:DigitalSourceType' \
-filename -DigitalSourceType *.jpg *.webp *.png
Google extracts these IPTC DigitalSourceType values:
trainedAlgorithmicMedia: fully AI-generated (use this for diffusion-model product imagery)compositeSynthetic: mixes captured + AI-generated elementsalgorithmicMedia: created purely by an algorithm, not from sampled training datacompositeWithTrainedAlgorithmicMedia: composite of trained algorithmic media + other media (e.g. AI inpainting/outpainting over a real photo)digitalCapture: fully captured photograph (note:digitalCaptureis not on Google's extracted-values list, but is a valid IPTC value)
Provenance signals (consumer-facing): SynthID watermarks and C2PA Content Credentials are emerging signals for AI media identification. Treat product-surface coverage as subject to change unless verified from a current Google-owned source. This is detection/transparency, not an extra required Merchant feed field beyond IPTC DigitalSourceType.
Licensable images: to earn the Licensable badge, supply EITHER structured data (
ImageObjectwith thelicenseproperty +acquireLicensePagefor the "Get this image" link) OR embedded IPTC photo metadata (Licensor URL / Web Statement of Rights). Cross-linkseo-schemafor the ImageObject markup.
Discovery note: image discovery now includes visual search fan-out across Lens / AI Mode / Circle to Search (Gemini multimodal scene/object understanding), so images surface via scene, objects, and materials, not alt text alone. No new published image-SEO lever yet; keep descriptive alt text + clean structured data.
When /seo images optimize is run on AI-generated assets, prompt the user to
confirm the source type and inject the matching IPTC value automatically.
For AI-generated product titles and descriptions, Google Merchant Center
also requires the AI-generated text to be separately specified and labeled in
the feed. This is enforced at the feed layer, not the page layer, flag this
in cross-reference with seo-ecommerce.
Metadata Audit
# Quick audit with exiftool
exiftool -IPTC:all -XMP:all -EXIF:ImageDescription image.jpg
# Batch audit - find images missing IPTC Creator
exiftool -if 'not $IPTC:By-line' -filename *.jpg *.webp *.png
Full Optimization Pipeline
For maximum image SEO, run this pipeline on each image:
- Audit existing metadata:
exiftool -IPTC:all -XMP:all image.jpg - Inject IPTC/XMP metadata: Creator, Copyright, Description
- Convert to WebP:
cwebp -q 82 -metadata all image.jpg -o image.webp - Generate responsive variants: 400w, 800w, 1200w
- Verify metadata preserved:
exiftool image.webp - Generate
<picture>HTML: AVIF > WebP > JPEG fallback chain
What Matters vs What Doesn't for Google Images
| Factor | Impact | Where to Set |
|---|---|---|
| Alt text | CRITICAL (ranking) | HTML <img alt=""> |
| Filename | HIGH (ranking) | File system (descriptive, hyphenated) |
| Page context | HIGH (ranking) | Surrounding HTML content |
| File size/speed | MEDIUM (indirect via CWV) | Compression + format conversion |
| IPTC Creator/Copyright | LOW (display only) | Image file metadata |
| EXIF camera data | NONE | Irrelevant for SEO |
| IPTC Keywords | NONE | Google ignores these |
Error Handling
| Scenario | Action |
|---|---|
| URL unreachable | Report connection error with status code. Suggest verifying URL and checking if site requires authentication. |
| No images found on page | Report that no <img> elements were detected. Suggest checking if images are loaded via JavaScript or CSS background-image. |
| Images behind CDN or authentication | Note that image files could not be directly accessed for size analysis. Report available metadata (alt text, dimensions, format from markup) and flag inaccessible resources. |
| exiftool not installed | Fall back to ImageMagick for metadata. Recommend: sudo apt install libimage-exiftool-perl |
| cwebp not installed | Fall back to ImageMagick or FFmpeg for WebP conversion. Recommend: sudo apt install webp |
| DataForSEO MCP not available | Skip Image SERP Analysis section. Note extension is not installed. |
Frequently asked questions about Image Optimization Analysis
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