PERF001 · Image dimensions
Severity: warning
What it checks
Section titled “What it checks”Every <img> element must have explicit width and height attributes set. Images missing either attribute are flagged.
Why it matters
Section titled “Why it matters”An <img> without explicit width and height triggers layout shift (CLS) as it loads, hurting Core Web Vitals and visual stability.
How to fix
Section titled “How to fix”Add explicit width and height attributes to the <img>:
<img src="/hero.jpg" width="1200" height="630" alt="…" />