WordPress Lazy Loading: Images, Iframes and the LCP Exception
Use lazy loading for below-the-fold media without delaying critical visual content.
Short answer: Lazy loading saves bandwidth and work by postponing off-screen media, but it should not blindly apply to the image that users need immediately. The likely LCP image usually deserves eager discovery and priority instead.
Lazy loading is most valuable for media the user may never scroll to.
Native lazy loading
Lazy loading is most valuable for media the user may never scroll to.
Always reserve width and height or an equivalent aspect ratio to reduce layout shift.
- Change one important variable at a time.
- Compare repeatable behavior rather than one isolated score.
- Keep reliability and maintainability ahead of marginal benchmark gains.
Below-the-fold images
Always reserve width and height or an equivalent aspect ratio to reduce layout shift.
Test carousels and dynamically inserted media because visibility detection can behave differently.
- Change one important variable at a time.
- Compare repeatable behavior rather than one isolated score.
- Keep reliability and maintainability ahead of marginal benchmark gains.
Iframe/video embeds
Test carousels and dynamically inserted media because visibility detection can behave differently.
Lazy loading is most valuable for media the user may never scroll to.
- Change one important variable at a time.
- Compare repeatable behavior rather than one isolated score.
- Keep reliability and maintainability ahead of marginal benchmark gains.
LCP image exclusions
Lazy loading is most valuable for media the user may never scroll to.
Always reserve width and height or an equivalent aspect ratio to reduce layout shift.
- Change one important variable at a time.
- Compare repeatable behavior rather than one isolated score.
- Keep reliability and maintainability ahead of marginal benchmark gains.
Layout dimensions
Always reserve width and height or an equivalent aspect ratio to reduce layout shift.
Test carousels and dynamically inserted media because visibility detection can behave differently.
- Change one important variable at a time.
- Compare repeatable behavior rather than one isolated score.
- Keep reliability and maintainability ahead of marginal benchmark gains.
Practical decision rule
Fix the layer the evidence points to. Caching helps repeated server work; CSS and JavaScript work affect rendering and responsiveness; images and fonts affect transfer and discovery; hosting and application behavior affect origin response. Avoid solving a different problem just because a tool is popular.
Related guides
Sources and further reading
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