Why doesn't my link preview show an image when I share my website?

What the crawler actually reads

When you paste a link, the platform does not look at your page the way a visitor does. A crawler requests the URL, reads the HTML the server sends back, and builds the card from a handful of meta tags in the head. The format most of them read is the Open Graph protocol, which lists og:image as one of its four required properties alongside og:title, og:type and og:url. Anything that only exists after your scripts run — tags injected by a client-side framework, an image set by a plugin in the browser — is invisible to most of these crawlers, because they do not run your code.

The image itself has to clear each platform's own bar, and the bars differ. Facebook's documentation asks for at least 1200 × 630 pixels for the best display, 600 × 315 as the minimum for a large-image post, never below 200 × 200, a ratio as close to 1.91:1 as possible and a file under 8 MB. LinkedIn's help centre sets its minimum at 1200 × 627, the same 1.91:1 ratio, and a 5 MB ceiling, and it names og:title, og:image, og:description and og:url as the tags it needs. One 1200 × 630 image under 5 MB satisfies both.

The usual causes, roughly in the order to check them

• There is no og:image on the page you shared. Most often the homepage has one and the inner pages do not — and inner pages are what people actually share.
• The image URL is relative. A path like /images/card.png means nothing to a crawler reading your HTML out of context. Every example in the Open Graph spec is a full https:// address; use one.
• The image is too small, too large, or the wrong shape. Below a platform's minimum you get a thumbnail or nothing; above its file-size limit it is dropped; a square or portrait image is cropped into the 1.91:1 frame.
• The crawler cannot reach it. A robots.txt rule, a login wall, a staging password or a firewall that blocks unfamiliar user agents stops the crawler before it sees a single tag.
• The platform is showing you an old copy. If the tag is correct today but was missing the first time the link was shared, the card you see is the cached one — see below.

What was wrong on our own site

Until 14 July 2026 no page on agentceres.com — the site of AgentCeres, the AI Growth Officer — carried an og:image, and every link we shared to Slack, X or LinkedIn unfurled as a bare text card. It took two independent fixes, and fixing either one alone would have left the site half broken.

The first was placement: the file that generates our card image sat at a level of the app that no page actually inherited from, so it applied to nothing. The second is a trap worth knowing if you build on Next.js. Its documentation says metadata from different levels is merged shallowly, and that nested fields like openGraph defined higher up are overwritten by the last level to define them. Our shared helper for page titles and descriptions set openGraph without an image, so on every page that used it — role pages, blog posts, comparison pages, the ones people share most — the page's own openGraph replaced the one that carried the card, image and all. Fixing only the placement would have left exactly the pages people share still without a picture. The lesson we kept: check the HTML of the exact page you are about to share, not just the homepage — inner pages are where these tags go missing.

Fixing the tag is only half of it

Platforms cache the preview they built the first time a link was shared, so a corrected page keeps showing the old card. Facebook states that images are cached by URL and are not updated unless the URL changes; its Sharing Debugger fetches your page again and shows you what its crawler now sees. LinkedIn's Post Inspector does the same for LinkedIn and is the fix its help centre gives for a preview showing an old image. Run the page through both after any change to its tags or image, and if a platform will not let go of an old image, give the image a new file name so its URL changes.

Previews matter more than they look. A lot of sharing happens in chat apps and DMs, where the card is the whole first impression and no referrer survives to tell your analytics where the visit came from — the traffic known as dark social. A link that unfurls as grey text in a group chat is easy to scroll past, and no report will ever show you the clicks it did not get. If you just changed the page and the live site itself still looks old, that is a different cache: see why your website still shows the old version.