What this problem is
Images are large and slow down page load times, increasing bandwidth and reducing Core Web Vitals.
Why it happens
- Uploading oversized originals
- No compression or wrong formats
- Too many unoptimized thumbnails
Prerequisites
- wp-admin access and basic media workflow access
Diagnosis
Use a performance report to identify the largest images and pages. Check image dimensions vs displayed size.
Detailed steps
Step 1) Resize before upload
Match typical display sizes (avoid uploading 4000px images for 800px display).
Step 2) Compress and convert formats
Use JPG/WebP/AVIF where appropriate. Keep logos/icons in SVG or PNG as needed.
Step 3) Enable lazy loading and proper caching
Lazy load below-the-fold images and set correct cache headers.
Step 4) Regenerate thumbnails if needed
After changing thumbnail sizes or optimization settings, regenerate thumbnails.
Expected results
- Smaller pages, faster load times, better Core Web Vitals
What to do if it fails
- If images look degraded, adjust compression levels and exclude specific images from aggressive optimization
Best practices
- Set an editorial guideline for image sizes and formats for content creators