Why File Size Matters
Every 100ms of load time costs 1% in conversions. Product images are typically the heaviest assets on e-commerce pages. Optimizing file sizes directly impacts page load speed, mobile experience, SEO rankings (Core Web Vitals), and hosting bandwidth costs.
Recommended Quality Settings
Main product image: WebP at 85% quality, 80-150KB. Thumbnail: WebP at 75%, 15-30KB. Zoom image: JPEG at 90%, 200-400KB. Transparent: PNG-8, 100-300KB. Social media: JPEG at 85%, 100-200KB.
Optimization Techniques
Choose the right format: WebP is best overall (30% smaller than JPEG, supports transparency), AVIF is newest and even smaller but has limited browser support, JPEG is universal fallback, PNG only when transparency is needed.
Resize before uploading — never upload 4000x4000 if it displays at 800x800. Strip EXIF metadata (adds 10-50KB per image). Use progressive loading for better perceived performance. Implement lazy loading to reduce initial page weight by 50-80%.
Measuring Results
Use Google PageSpeed Insights to check Largest Contentful Paint (under 2.5s), total image weight (under 500KB per page), and properly sized images.