methodology / Performance / #35

Lazy loading on below-fold images

live factor #35 · Performance · scoring impl: implemented · weight 0.7%

What we measure

Lazy-loaded images don't download until visitors scroll near them, cutting initial page weight and speeding up first paint.

How to improve your score

Add `loading="lazy"` to `<img>` tags below the fold. WordPress 5.5+ adds it automatically. Don't lazy-load above-fold or hero images — that delays LCP.

Data source

Data source for this factor is not yet documented.

Implementation notes

Count `<img>` tags with vs without the `loading="lazy"` attribute and report the ratio.

Scoring

Scoring formulas are versioned with the methodology. The current method (v1.1.0) maps raw measurements to pass, warn, fail. Factor weights determine how much each contributes to the composite — see the methodology index for the full table.

Version history

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