seo-images

seo-images is a skill for Claude Code from lionkiii/claude-seo-skills. It costs 94 tokens per session (1,537 once invoked), scanned A, original, MIT.

An image review for search visibility and page performance. It checks alternative text, file size, image format, responsive delivery, lazy loading, and measures that help prevent layout shifts.

In plain words
What is it for?
Use it to audit images for useful alt text, suitable compression and formats such as WebP or AVIF, and safer loading behavior.
Why use it?
It identifies image problems that can make pages slower, less accessible, or harder for search engines to understand.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the claude-seo-skills plugin — 51 skills, 6 agents shipped together

Good fit Use it to audit images for useful alt text, suitable compression and formats such as WebP or AVIF, and safer loading behavior.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/lionkiii/claude-seo-skills/seo-images
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add lionkiii/claude-seo-skills --skill seo-images
Clone the repo
git clone --depth 1 https://github.com/lionkiii/claude-seo-skills

Made for: Claude Code.

Or install claude-seo-skills, the plugin that ships this one along with the rest of its 51 skills, 6 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for seo-images

README.md
[![agentmods](https://agentmods.dev/badge/skills/lionkiii/claude-seo-skills/seo-images/github.svg)](https://agentmods.dev/skills/lionkiii/claude-seo-skills/seo-images)
Your own site
<a href="https://agentmods.dev/skills/lionkiii/claude-seo-skills/seo-images"><img src="https://agentmods.dev/badge/skills/lionkiii/claude-seo-skills/seo-images/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for seo-images

Your own site · 80×15
<a href="https://agentmods.dev/skills/lionkiii/claude-seo-skills/seo-images"><img src="https://agentmods.dev/badge/skills/lionkiii/claude-seo-skills/seo-images.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 94 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,537 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00094 $0.01537
Opus 5 $0.00047 $0.00768
Sonnet 5 $0.00019 $0.00307
Haiku 4.5 $0.00009 $0.00154

Measured 12d ago against content hash 24483403b7fe, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

seo-images scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/seo-images/SKILL.md · 183 lines

How it starts

The opening of the file, as written. The whole thing — 183 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Image 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
  • Place images near relevant text on pages relevant to the image subject — Google uses alt text along with surrounding page content to understand the image (per Google Images best practices)

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 Universal (~100%) Default recommendation
AVIF ~95%+ 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 ~95%+, WebP universal.

Read the full file on GitHub · 183 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 12d ago First seen · 183 lines · 94 tokens per session scan A 24483403b7fe

Subscribe to this mod's changes

seo-images is a skill published in the GitHub repository lionkiii/claude-seo-skills (20 stars, last pushed 3mo ago), licensed MIT. It adds 94 tokens to every session and 1,537 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.