A 30-minute image pass that almost always lifts LCP

For most WordPress sites, the Largest Contentful Paint is an image. Often the hero image. Often that image is 800KB of unoptimised JPG. A 30-minute pass on images alone usually moves mobile performance from the red into the yellow.

The pass

1. Identify the LCP candidate in PageSpeed.
2. Convert it (and friends) to WebP, compress sensibly.
3. Set explicit width and height attributes.
4. Make sure it is not lazy-loaded.
5. Add fetchpriority="high" if your theme allows it.
6. Re-run PageSpeed.

I do this on almost every Collaborate Pros audit. It works.