What is measured
The audit counts images missing either dimension attribute in the source HTML.
Content and images
Image dimensions
This check finds img elements without declared width and height, which prevents the browser reserving space early.
Pass criterion
Every image supplies dimensions or receives a stable aspect ratio through its component and CSS.
What to fix
Add width and height from the source file, scale responsively and avoid changing proportions in styles.
Automation limit
Dimension attributes improve stability but do not guarantee an optimal file weight, format or visual quality.
Reference