Image Optimization Skill for Claude

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.

486 tokens

context cost

SKILL.md, read when the skill is used

files

instructions only

copies elsewhere

how many repositories repackaged it

202

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/secondsky/claude-skills --skill image-optimization

The instruction itself

7 sections, as written by the author

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

<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

<!-- 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)

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

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How to use it

Copy the folder

Take secondsky/image-optimization from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.