Why does Lighthouse want width and height on my images?

Setting an explicit width and height on every image is the single most effective fix for Cumulative Layout Shift - the annoying jump as a page loads. It tells the browser exactly how much space to reserve before the image arrives:

• Without dimensions - the browser does not know how tall the image is, so it leaves no gap, then shoves everything down when the image loads.
• With dimensions - the space is reserved from the start, so nothing moves and CLS stays low.
• It is a tiny change - two attributes on the image tag, or the matching settings in your page builder.

This costs nothing and asks for no design change, yet it fixes the layout-shift problem most sites have. Add width and height to every image - it is the cheapest Core Web Vitals win there is.