Image Optimization for SEO: Formats, Compression, and Alt Text
Master image optimization for faster page loads and better search rankings. Covers WebP, AVIF, lazy loading, responsive images, and alt text best practices.
Images account for the largest portion of page weight on most websites — often 50-80% of total bytes. Optimizing images is the single most impactful action you can take to improve page speed, Core Web Vitals scores, and search engine rankings.
Modern formats matter: WebP provides 25-35% smaller files than JPEG with equivalent quality, and browser support is now universal. AVIF goes further with 50% savings, though encoding is slower. For maximum compatibility, serve AVIF with WebP and JPEG fallbacks using the <picture> element.
Compression should be aggressive but intelligent. For photographs, JPEG quality 75-85 or WebP quality 75-80 provides excellent results with minimal visible degradation. For screenshots and diagrams with sharp text, PNG or WebP lossless gives pixel-perfect rendering.
Properly sized images are crucial — never serve a 4000×3000 pixel image when the display size is 800×600. Use responsive image srcset attributes to serve different sizes at different breakpoints. This alone can reduce image bytes by 60-80%.
ConvertCraft's Image Converter helps with bulk format conversion and compression — convert entire folders of JPEGs to WebP, resize batches to specific dimensions, or strip EXIF metadata for privacy. All processing happens in your browser with zero upload.