Individual skill
progressive-jpeg
Use when reviewing image assets, markup, and CDN or build transforms related to Use progressive JPEG encoding. Check encoded size, rendered size, loading strategy, and above-the-fold impact together.
skills/progressive-jpeg/SKILL.md
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- Last checked
- Nov 9, 2026
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- Repository last updated
- Oct 31, 2026
- License
- MIT
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- frontend Repository topic
- front-end-development Repository topic
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- reference Repository topic
- web-development Repository topic
- html Repository topic
- css Repository topic
- javascript Repository topic
- engineering Derived category
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SKILL.mdcore · 1,705 bytesreferences/rule.mddoc · 4,331 bytes
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# Use progressive JPEG encoding
Progressive JPEGs display a low-quality preview immediately rather than loading line-by-line—users see something faster, improving perceived performance even if total load time is similar.
## Quick Reference
- Progressive JPEGs show blurry preview immediately, then sharpen
- Better perceived performance than baseline JPEGs that load top-to-bottom
- Similar file size to baseline JPEG (sometimes slightly smaller)
- Less relevant with modern formats (WebP, AVIF) but still useful for fallbacks
## Check
Check if JPEG images are saved in progressive format for better perceived performance.