Lazy-loaded images declare dimensions

Class

C3 Standard

Weight

2

Severity on fail

minor

Applies to

the HTML Standard

Scope and evidence

Evaluated on page (P). The book marks this requirement STANDARD.

Fail conditions

Each condition has a stable code and a reason template. The evaluator fills the placeholders from observed values only; no sentence in a report is generated.

• lazy_without_dimensions

  {n} lazy-loaded images on {url} lack width or height, for example {src}. The HTML Standard advises dimensions on lazy-loaded images to prevent the page layout from shifting around after the image loads.

The documented fix

Store intrinsic dimensions at upload and render them as width and height attributes.

Sources, quoted

These are the passages the rule rests on, stored once in the knowledge base and emitted exactly as written. A citation marked for specific conditions appears only on findings with those codes.

• “to prevent the page layout from shifting around after the image loads”

  [WHATWG-EMBED] HTML Standard: 4.8 Embedded content (img, lazy loading) · 4.8.3 The img element · last updated Living Standard

  https://html.spec.whatwg.org/multipage/embedded-content.html