Missing image size: what it means and how to fix it

What we look for

Some images on these pages lack a width or height attribute in their HTML. Images placed with absolute or fixed positioning are skipped.

Why it matters

Without both, the browser cannot save space for an image before it loads, so the page jumps as images appear. Google measures that jumping as CLS (Cumulative Layout Shift), one of its Core Web Vitals (page experience scores).

How to fix

Add width and height attributes with each image's real size in pixels, in the page template or CMS. CSS can still resize the image, and the browser keeps its shape.

What it cannot know

Sizes set only in CSS, or written as percentages, count as missing here.

Where you’ll see it

The id is stable, and every surface uses it, so it’s the thing to search for or hand to an agent.

Terminal: When it is one of the five findings under Fix first, raptor crawl prints the id under it.
Check: images.missing_dimensions
crawl.json and the CSV: The crawl JSON names the finding by this id, and so do the CSV and raptor_query.
"check_id": "images.missing_dimensions"
The HTML report: This link opens the finding in the report, and each finding shows its id.
crawl.html#finding=images.missing_dimensions
MCP: raptor_findings with this check_id returns the finding in full, with a fix brief ready to paste into a task. If it didn’t fire, it says why.
raptor_findings { "job_id": "...", "check_id": "images.missing_dimensions" }