Images are usually the heaviest part of a WordPress page. Uploading phone photos straight to the Media Library can add several megabytes to every page and drag down your Google PageSpeed score.
Follow this checklist before uploading and your site will feel noticeably faster.
In this guide
- 1. Resize before uploading
- 2. Compress every image
- 3. Use WebP
- 4. Name files and add alt text
- 5. Enable lazy loading and caching
- 6. Test the result
1. Resize before uploading
Most themes display content images no wider than 1200–1600 pixels. Resize larger photos to that width first — WordPress creates thumbnails, but it keeps your huge original too.
2. Compress every image
Run each image through our free Image Optimizer. Aim for under 150 KB for blog images and under 300 KB for full-width hero images.
3. Use WebP
WordPress has supported WebP uploads since version 5.8. Convert with our JPG to WebP or PNG to WebP tools for 25–35% smaller files.
4. Name files and add alt text
Use descriptive file names like blue-running-shoes.webp instead of IMG_4821.jpg, and write meaningful alt text. Both help image SEO and accessibility.
5. Enable lazy loading and caching
WordPress lazy-loads images by default. Add a caching plugin and, ideally, a CDN. Avoid lazy-loading the main above-the-fold image, as that can hurt Largest Contentful Paint.
6. Test the result
Check your page in Google PageSpeed Insights before and after. Also confirm your server uses modern compression with our Brotli Checker and HTTP/2 Checker.
Frequently asked questions
Do I need an image optimisation plugin?
Plugins are convenient, but compressing before upload works just as well and keeps your site lighter.
What image size is best for WordPress featured images?
Commonly 1200×628 pixels, which also suits social sharing previews.
Does image compression affect SEO?
Faster pages improve user experience and Core Web Vitals, which support rankings.
