P2 · MediumPerformance

No modern image formats

Images not using WebP or AVIF

Code: no_modern_image_format

Why it matters

Images not using WebP or AVIF. Slow experiences increase bounce rates and hurt Core Web Vitals scores. Google uses these metrics as a direct ranking signal.

How to fix

Use WebP/AVIF with fallback

html

<picture>
  <source srcset="image.avif" type="image/avif">
  <source srcset="image.webp" type="image/webp">
  <img src="image.jpg" alt="Description" width="800" height="600">
</picture>

Related checks in Performance

Slow First Contentful Paint

FCP exceeds 3 seconds

FCP needs improvement

FCP between 1.8-3 seconds

Slow Largest Contentful Paint

LCP exceeds 4 seconds

LCP needs improvement

LCP between 2.5-4 seconds

Poor Cumulative Layout Shift

CLS exceeds 0.25

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