LCP · high impact

LCP image is too heavy

The Largest Contentful Paint (LCP) image has a large file size, which takes too long to download.

Why it matters

Large images are the most common cause of slow LCP. Compressing and serving in modern formats (like WebP) can drastically cut download times.

How to fix it in WordPress

  1. Install an image optimization plugin (like ShortPixel, Imagify, or Smush) if you haven't already.
  2. Configure the plugin to compress images and serve them in WebP format.
  3. Run a bulk optimization on your Media Library.

Plugin-specific steps

Already using one of these plugins? Follow the exact steps for your setup.

ShortPixel

  1. 1Go to Settings → ShortPixel.
  2. 2Ensure 'Compression type' is set to Lossy (or Glossy if you need higher quality).
  3. 3Check the box to 'Create WebP versions of the images'.
  4. 4Go to Media → Bulk ShortPixel and optimize the LCP image.

Imagify

  1. 1Go to Settings → Imagify.
  2. 2Ensure the optimization level is set to 'Smart'.
  3. 3Check the option to create WebP versions of images.
  4. 4Go to Media → Bulk Optimization and optimize the library.

How to verify the fix

  • Open the page in an incognito window.
  • Right-click the hero image and check if it is served as a WebP file.
  • Verify the file size is significantly smaller.

Related LCP fixes

Your main image is lazy-loaded (LCP penalty) →Your main image isn't prioritized →Eliminate render-blocking CSS →

Find out which of these your site has.

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