One problem, explained
Why your link shows no image when shared.
You post your page on X, LinkedIn, Slack or WhatsApp and it appears as bare text next to posts with pictures. The cause is almost always one of four things, and all of them are visible from the outside.
The checker reads your page and tells you whether the tags are there.
The four causes
- 01
There is no og:image tag at all
The most common case by far. Without <meta property="og:image" content="https://yoursite.com/card.png">, every app falls back to text. Three of the first pages I checked this week had none, including two that grow by being shared.
- 02
The image URL is relative, or points to a page that needs JavaScript
Preview bots do not run your app. The value has to be a full https:// address that returns an image file directly, not a route that renders one.
- 03
The image is marked private for caches
A Cache-Control header of private or no-store makes some preview services skip the file. Serve the card with a public cache, for example public, max-age=86400.
- 04
The file is too big, too small, or the wrong type
Aim for 1200 x 630 pixels, PNG or JPEG, under 1 MB. Under 300 x 157 is rejected outright. SVG and WebP are refused by several platforms.
The fix, in order
- Add og:image, og:title and og:description in your <head>, plus twitter:card set to summary_large_image.
- Make the image URL absolute and stable. Avoid query strings that change.
- Serve it with a public cache header and a correct image content type.
- Re-share the link with a fresh URL, because platforms cache a preview per address for days.
One warning from my own experience: X sometimes checks that the image exists and never downloads it, so a card can stay text-only on that platform while it renders correctly everywhere else. That one is not yours to fix.
While you are here
A missing preview image is one of sixteen things a machine can check on your page. The other four are why pages with a perfect score still sell nothing.