30x-seo-imageslisted
Install: claude install-skill square-lupus579/30x-seo
# 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
**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: