Agent skill

Image Optimization

Optimizes images for web performance using modern formats, responsive techniques, and lazy loading strategies.

Install Image Optimization

skills CLI

$ npx skills add secondsky/claude-skills --skill image-optimization -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills image-optimization --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/image-optimization/skills/image-optimization .claude/skills/image-optimization && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "image-optimization" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/image-optimization/skills/image-optimization into .claude/skills/image-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "image-optimization", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/secondsky/claude-skills/tree/main/plugins/image-optimization/skills/image-optimization

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add secondsky/claude-skills --skill image-optimization -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills image-optimization --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/plugins/image-optimization/skills/image-optimization .agents/skills/image-optimization && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "image-optimization" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/image-optimization/skills/image-optimization into .agents/skills/image-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "image-optimization", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add secondsky/claude-skills --skill image-optimization -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills image-optimization --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/plugins/image-optimization/skills/image-optimization .cursor/skills/image-optimization && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "image-optimization" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/image-optimization/skills/image-optimization into .cursor/skills/image-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "image-optimization", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/secondsky/claude-skills.git --path plugins/image-optimization/skills/image-optimization

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add secondsky/claude-skills --skill image-optimization -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills image-optimization --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/plugins/image-optimization/skills/image-optimization .gemini/skills/image-optimization && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "image-optimization" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/image-optimization/skills/image-optimization into .gemini/skills/image-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "image-optimization", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install secondsky/claude-skills image-optimization

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add secondsky/claude-skills --skill image-optimization -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/plugins/image-optimization/skills/image-optimization .github/skills/image-optimization && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "image-optimization" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/image-optimization/skills/image-optimization into .github/skills/image-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "image-optimization", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add secondsky/claude-skills --skill image-optimization -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills image-optimization --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/plugins/image-optimization/skills/image-optimization .opencode/skills/image-optimization && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "image-optimization" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/image-optimization/skills/image-optimization into .opencode/skills/image-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "image-optimization", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: image-optimization
GitHub stars: 227
Token cost: ~487 tokens
SKILL.md length: 94 words
Files: 1
Skills in repo: 169
Repo updated: Sep 28, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Optimizes images for web performance using modern formats, responsive techniques, and lazy loading strategies.

Improving page load times
SKILL.md covers Format Selection, Responsive Images, Lazy Loading and Build Pipeline (Sharp), plus 2 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
Implementing responsive images

What it does

Image Optimization is an agent skill from secondsky/claude-skills. Optimizes images for web performance using modern formats, responsive techniques, and lazy loading strategies. Use when improving page load times, implementing responsive images, or preparing assets for production deployment.

Its SKILL.md is about 490 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Frontend & Design, covering Web performance. The repository describes itself as: Production-ready skills for Claude Code CLI - Cloudflare, React, Tailwind v4, and AI integrations. The licence is MIT.

When your agent uses it

Improving page load times
Implementing responsive images
Preparing assets for production deployment

Example prompts

“Use the image-optimization skill to optimiz images for web performance using modern formats, responsive techniques, and lazy loading strategies”
“/image-optimization”

What it can do on your machine

Read from SKILL.md and the folder at commit 8837836. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are html and javascript).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Image Optimization loads about 487 tokens when it runs. Until then it costs about 61 tokens; SKILL.md has 94 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~61
When it runs · the whole SKILL.md, loaded when a task matches: ~487

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from secondsky/claude-skills at commit 8837836, republished under its MIT licence (© secondsky). 94 words, ~487 tokens.

Download SKILL.mdSave it as .claude/skills/image-optimization/SKILL.md (or your agent's skills folder).

name: image-optimization
description: Optimizes images for web performance using modern formats, responsive techniques, and lazy loading strategies. Use when improving page load times, implementing responsive images, or preparing assets for production deployment.
license: MIT

Image Optimization

Optimize images for web performance with modern formats and responsive techniques.

Format Selection

Format	Best For	Compression
JPEG	Photos	Lossy, 50-70% reduction
PNG	Icons, transparency	Lossless, 10-30%
WebP	Modern browsers	25-35% better than JPEG
AVIF	Next-gen	50% better than JPEG
SVG	Logos, icons	Vector, scalable

Responsive Images

html

<picture>
  <source srcset="image.avif" type="image/avif">
  <source srcset="image.webp" type="image/webp">
  <img
    src="image.jpg"
    srcset="image-400.jpg 400w, image-800.jpg 800w, image-1200.jpg 1200w"
    sizes="(max-width: 600px) 100vw, 50vw"
    alt="Description"
    loading="lazy"
    decoding="async"
  >
</picture>

Lazy Loading

html

<!-- Native lazy loading -->
<img src="image.jpg" loading="lazy" alt="Description">

<!-- With blur placeholder -->
<img
  src="placeholder-blur.jpg"
  data-src="image.jpg"
  class="lazy"
  alt="Description"
>

Build Pipeline (Sharp)

javascript

const sharp = require('sharp');

async function optimizeImage(input, output) {
  await sharp(input)
    .resize(1200, null, { withoutEnlargement: true })
    .webp({ quality: 80 })
    .toFile(output);
}

Performance Targets

Asset Type	Target Size
Hero image	<200KB
Thumbnail	<30KB
Total images	<500KB

Optimization Checklist

Use WebP with JPEG fallback
Implement responsive srcset
Enable lazy loading for below-fold
Compress at quality 70-85
Serve from CDN
Set proper cache headers

Files

Just SKILL.md in plugins/image-optimization/skills/image-optimization of secondsky/claude-skills.

Open the folder on GitHubat commit 8837836

Compare with similar skills

Image Optimization next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Image Optimization compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Image Optimization this skillsecondsky/claude-skills	227	—	~487	Automated safety check: Pass	MIT	9 days ago
React Doctormakeplane/plane	61k	12 repos	~657	Automated safety check: Pass	AGPL-3.0	today
Fixing Motion Performanceibelick/ui-skills	9.5k	5 repos	~1.4k	Automated safety check: Pass	MIT	today
GSAP Performance Tuninggreensock/gsap-skills	16k	4 repos	~1k	Automated safety check: Pass	MIT	2 mo ago
React Frontend Development Guidelinesdiet103/claude-code-infrastructure-showcase	10k	2 repos	~2.9k	Automated safety check: Pass	MIT	2 mo ago
Web Quality Auditaddyosmani/web-quality-skills	2.9k	—	~2.6k	Automated safety check: Pass	MIT	1 mo ago

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Questions about Image Optimization

What does Image Optimization do?

Optimizes images for web performance using modern formats, responsive techniques, and lazy loading strategies. Image Optimization is an agent skill from secondsky/claude-skills. Optimizes images for web performance using modern formats, responsive techniques, and lazy loading strategies.

When should I use Image Optimization?

Image Optimization fits situations like: improving page load times; implementing responsive images; preparing assets for production deployment.

How do I install Image Optimization in Claude Code?

Run `npx skills add secondsky/claude-skills --skill image-optimization -a claude-code`. Or copy the skill folder (plugins/image-optimization/skills/image-optimization in secondsky/claude-skills) into .claude/skills/image-optimization in your project. Claude Code loads it when a task matches its description.

How do I install Image Optimization in Codex?

Run `npx skills add secondsky/claude-skills --skill image-optimization -a codex`. Or copy the skill folder (plugins/image-optimization/skills/image-optimization in secondsky/claude-skills) into .agents/skills/image-optimization in your project. Codex loads it when a task matches its description.

Can I use Image Optimization in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add secondsky/claude-skills --skill image-optimization -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/image-optimization, .gemini/skills/image-optimization, .github/skills/image-optimization and .opencode/skills/image-optimization in your project.

What does Image Optimization need to run?

SKILL.md names no scripts, command-line tools or credentials: Image Optimization is instructions for the agent only.

Does Image Optimization access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Image Optimization safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Image Optimization use?

Image Optimization is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Image Optimization use?

About 487 tokens (SKILL.md is roughly 1.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Image Optimization?

Skills that share tags, products or a category with Image Optimization: React Doctor (makeplane/plane, 61k stars), Fixing Motion Performance (ibelick/ui-skills, 9.5k stars), GSAP Performance Tuning (greensock/gsap-skills, 16k stars) and React Frontend Development Guidelines (diet103/claude-code-infrastructure-showcase, 10k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Image Optimization?

secondsky (a GitHub user) maintains it in secondsky/claude-skills, which has 227 GitHub stars. The repository holds 169 skills in this directory. The repository was last updated on September 28, 2026.

Source: secondsky/claude-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Image Optimization

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Image Optimization

Format Selection

Responsive Images

Lazy Loading

Build Pipeline (Sharp)

Performance Targets

Optimization Checklist

Files

Compare with similar skills

Similar skills

More from secondsky/claude-skills

Related

Questions about Image Optimization