Sign in Get Started

Troubleshooting common issues with Optimize LCP Images within Jetpack Boost

If Jetpack Boost is not optimizing your Largest Contentful Paint (LCP) images as expected, this guide helps you identify common issues and resolve problems reported during LCP analysis.

View LCP Optimization issues

If Jetpack Boost cannot optimize one or more Cornerstone Pages, an LCP Optimization issues notice appears in the Images section.

To review the issue:

  1. Go to Jetpack → Boost in WP Admin.
  2. Under Optimize your speed, expand the Images section.
  3. Find LCP Optimization issues below Optimize LCP Images.
  4. Select the “View details” link to see the affected pages and the reason each page could not be optimized.

Pages not being optimized

Check page availability

Confirm that Jetpack Boost can reach the pages you want optimized:

  • Ensure your important pages are publicly available, and not password protected.
  • Verify pages return a 2XX HTTP response (not 404 or server errors).

Review page structure

The layout of a page affects how reliably Boost can detect the LCP element:

  • Pages with one clear, prominent visual element work best.
  • Multiple competing large images can complicate LCP detection.
  • Very complex layouts may require manual optimization.

Optimization results not visible

Clear caches

Cached versions of a page can hide the optimizations Boost applied. Clear each cache in turn:

  • Clear your site’s page cache.
  • Clear the CDN cache if applicable.
  • Test in a private or incognito browser window.

Verify implementation

On a Cornerstone Page, view the page source and look for the following attributes:

  • fetchpriority="high" on optimized images.
  • loading="eager" instead of lazy loading.
  • data-jp-lcp-optimized="true"

Troubleshoot LCP Optimization issues

When Boost cannot optimize a page, it displays an explanation under LCP Optimization issues. Select the “Learn more” link for an affected page to open the relevant troubleshooting section below.

HTTP error

Cause

Jetpack Boost encountered an HTTP error while attempting to analyze the page.

Solution

Open the affected page in a private or incognito browser window and make sure it loads correctly. Then try the optimization again.

Page took too long to load

Cause

The page took too long to load during analysis.

Solution

Open the affected page in a private or incognito browser window and make sure it loads correctly. Then try the optimization again.

Main LCP element could not be identified in time

Cause

Jetpack Boost loaded the page successfully, but could not identify the main LCP element within the time limit. This may happen with slow-loading or complex pages.

Solution

Make sure the page presents stable visual content that Boost can measure:

  • Ensure the page has visual content that loads within a reasonable timeframe.
  • Check for JavaScript errors or infinite loading states that prevent content from stabilizing.
  • Verify the page isn’t primarily empty, redirect-heavy, or composed entirely of dynamically-loaded content.

Multiple similar large elements found

Cause

Jetpack Boost found multiple similar large elements with the same selector and could not identify which one should be treated as the main LCP element.

Solution

Help Boost identify a single dominant element:

  • Simplify your layout or ensure there’s one clearly dominant visual near the top of the page.
  • Avoid having multiple competing hero images or background sections above the fold.

Main LCP element did not remain visible

Cause

Jetpack Boost identified a potential LCP element, but it did not remain visible long enough to analyze. This can happen with slideshows, animated sections, or other content that changes soon after the page loads.

Solution

Keep the LCP element visible long enough for Boost to measure it:

  • Keep the hero/LCP element visible for at least 3 seconds during initial load (for example, pause or delay autoplay/rotation).
  • Set the slider to start on the hero slide and delay the first transition (3 seconds or more).
  • Minimize heavy entrance animations that immediately replace the hero content.
  • If you cannot make these changes yourself (for example, using a theme or slider plugin without settings):
    • Contact the theme or slider plugin authors and request that their carousel respects prefers-reduced-motion: reduce (pause or disable autoplay and transitions when users prefer reduced motion).
    • Ask for a setting to disable or delay autoplay on initial load so the main slide remains visible long enough for analysis.

Page redirected during analysis

Cause

The page redirected to another URL during analysis, so Jetpack Boost could not measure its LCP. When the cloud reports the redirect target, Boost shows it as the final URL in the error message. Common causes include canonical redirects, trailing slash redirects, locale redirects, and geo redirects, as well as login walls.

Solution

Resolve the redirect so Boost analyzes a page that loads directly. Choose one of the following:

  • Remove the URL from your Cornerstone Pages.
  • Point the Cornerstone Pages entry at the final destination URL.
  • Remove the redirect so the page loads without redirecting.

Something went wrong during optimization

Cause

Jetpack Boost could not determine the cause of the issue during optimization.

Solution

Wait a few minutes and try the optimization again.

If the issue continues, contact support.

Still need help?

If you still need assistance, contact support. We are happy to advise.