1.5 Performance & Core Web VitalsMediumVerified
Images without width/height
An image with no width and height has no reserved space, so the page reflows when it loads. Setting intrinsic dimensions is the single most effective fix for layout shift.
What it is
Missing intrinsic dimensions.
Why it matters
Causes layout shift (CLS).
How to fix it
Set width/height or CSS aspect-ratio.
How to find it on your site
- Inspect img tags and check for width and height attributes, or a CSS aspect-ratio.
- Find images that load without reserved space.
- Add intrinsic width and height so the browser reserves the box.
- Re-measure CLS to confirm the shift is gone.
Cross-reference to ranking and citation factors
This directly improves CLS, a Core Web Vital. It is low-effort and high-impact for layout stability.
Impact
Low-medium. Direct (CLS driver).
Evidence
Set dimensions to avoid layout shift. web.dev, Core Web Vitals (Google)