Image SEO audit — make a site's images discoverable in Google Images and stop them from dragging down Core Web Vitals. Audits alt text quality and coverage, descriptive file names, modern formats (WebP/AVIF), dimensions and compression, responsive srcset, lazy-loading, explicit width/height (CLS), image sitemaps, and ImageObject structured data.
NewMaintained
Automatic
◆Marketing & Content pack
Last verified 8/17/2026
What it changes
Passed 8 of 23 test cases with the skill, and 15 of 23 without it.
Without skill67%
With skill33%
Checks it passed that the model alone missed
The Open Graph image markup includes the og:image:width property.
1 fixed20 passed either way0 still failing2 broke
Pass-rate lift
-33 pp
Tokens
-1%
Agent turns
0%
Response time
+1%
Measured 8/17/2026v2 · latest is v321 of 23 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
This benchmark measured an earlier version of the skill.
A newer attempt on gemini-3.8-flash on 10/19/2026 did not produce a publishable comparison (not comparable). The snapshot above is the previously measured run.
See it in action
A test case the skill fixed. Same model, same prompt, with and without the skill.
Prompt
We are updating our travel blog's article about hiking in Yosemite. Please review our current list of blog post images and generate search-engine-optimized alt tags, title attributes, contextually relevant caption suggestions, and social media Open Graph image tag values organized in a clean markdown table.
What was checked, without and with the skill
Checked
Without skill
With skill
The alt text excludes redundant phrases like 'image of'.
Passed
Passed
The Open Graph image markup includes the og:image:width property.
Missed
Passed
Recommended image filenames use hyphens rather than underscores.
Passed
Passed
case-01 · gemini-3.6-flash · 8/17/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md3 linessingle file
Canonical NotFair workflow
Read ../../seo/image-seo/WORKFLOW.md completely, then follow it as the active workflow. Resolve every relative reference from that file against ../../seo/image-seo/.