WordPress sites with unoptimised images are slower, rank lower in Google, and provide a poor user experience on mobile. Image optimisation is one of the fastest wins available for WordPress SEO — often improving PageSpeed scores dramatically with minimal effort.
Why WordPress Image Optimisation Matters
- Google uses page speed as a ranking factor — slow sites rank lower
- Core Web Vitals (LCP, FID, CLS) are directly affected by image performance
- Mobile users on limited data connections abandon slow-loading pages
- Google Image Search drives significant traffic to well-optimised image content
WordPress Image Optimisation Checklist
- Resize before uploading: Use imgresizr.com to resize to maximum display dimensions — never upload 4000px images to a 800px wide blog
- Choose the right format: JPG for photos, PNG for screenshots/graphics, WebP for best performance
- Compress: Use imgresizr.com's compress tool to reduce file size before uploading
- Name files properly: "blue-leather-sofa.jpg" not "IMG_3421.jpg"
- Add alt text: Fill in every image's alt text field in WordPress media library
- Install a WebP plugin: Plugins like Imagify or ShortPixel convert uploaded images to WebP automatically
- Enable lazy loading: WordPress 5.5+ includes native lazy loading
WordPress Image Size Settings
WordPress creates multiple size variants of every uploaded image. Set sensible limits in Settings > Media to avoid enormous file sizes. Typical settings: thumbnail 150×150, medium 600×600, large 1200×1200. Delete sizes you do not use with a plugin like Regenerate Thumbnails.
Prepare and optimise all WordPress images at imgresizr.com before uploading — free, fast, and SEO-ready.