Optimizing web images reduces Largest Contentful Paint (LCP) render times and eliminates Cumulative Layout Shift (CLS) layout jumps.

Responsive HTML5 Picture Element

optimized_image.htmlhtml
<picture>
    <!-- Modern AVIF format for supporting browsers -->
    <source srcset="hero-800.avif 800w, hero-1200.avif 1200w" type="image/avif">
    <!-- WebP fallback -->
    <source srcset="hero-800.webp 800w, hero-1200.webp 1200w" type="image/webp">
    <!-- Legacy JPEG fallback with explicit aspect ratio attributes -->
    <img src="hero-800.jpg" width="800" height="450" alt="Engineers working" loading="lazy">
</picture>