How your links look when people share them

Last updated 14 October 2026

By the FocalScore team at Astrolabix LLC. First published 14 October 2026. Sources last checked October 2026.

The short answer

When someone pastes your link into WhatsApp, Facebook, LinkedIn or a text message, the app shows a title, a line of text and a picture that it reads from tags in your page's head. Set those tags on each page you expect people to share, use a picture 1200 by 630 pixels that is well under 5 MB, and make sure nothing stops the apps fetching the page or the picture.

What makes a link preview

The preview comes from Open Graph tags, a standard first written by Facebook and now read by most apps that show previews:

<meta property="og:title" content="Boiler repairs and servicing">
<meta property="og:description" content="Local, qualified engineers. Call for a free quote.">
<meta property="og:image" content="https://www.yoursite.com/images/share-boiler.jpg">
<meta property="og:url" content="https://www.yoursite.com/boiler-repairs/">
<meta property="og:type" content="website">
<meta name="twitter:card" content="summary_large_image">

The last line is for X: summary_large_image asks for the full-width picture rather than a small square thumbnail. When the tags are missing, each app guesses from the page, often picking a logo, an icon or nothing at all.

Why it matters to a small business

Recommendations travel as links: a customer sends your page to a friend, a local group shares your offer. The preview is the first thing the person receiving it sees. A clear picture and a title that says what the page offers make it look like a business worth opening; a grey box with your web address looks like nothing.

How the free scan decides

Open Graph / Twitter cards fails when the homepage has no share tags, and Share previews on inner pages when only the homepage has its own preview and inner pages repeat it or have none.
Large social preview image fails when the twitter:card tag asks for the small thumbnail layout.
Social preview image is crawlable fails when robots.txt blocks the share picture, so apps can't fetch it.
Your social preview image is small enough to share fails when the picture is over 8 MB, Facebook's limit, and warns over 5 MB, LinkedIn's.
Link previews get the same page you do fails when the services that build previews are sent different content from a browser, such as a security challenge page instead of yours.

The share picture

Make it 1200 by 630 pixels, the size Meta recommends for a full-width preview. LinkedIn's specification is close to the same shape, so one picture serves both.
Save it as a JPG or PNG and keep the file well under 5 MB.
Keep words and faces away from the edges: some apps crop the picture to a square or a narrower strip.
Use the full address, starting with https://, in og:image, and check it opens in a private browser window.
If robots.txt blocks the folder the picture is in, allow that file or move it somewhere that isn't blocked.

Where to set it, by platform

WordPress: an SEO plugin adds the tags. Each page and post gets a social tab in the plugin's box under the editor, where you set the title, description and image; the plugin's settings hold the default image for pages without one.
Shopify: the site-wide social sharing image is in the online store's preferences, and product pages use the product's main image. Most themes write the tags for you.
Wix and Squarespace: each page's SEO or social settings have a social image and text, and the site settings hold a default social image.
A hand-built site or ASP.NET: put the tags in each page's head. On ASP.NET MVC they usually sit in the shared layout (_Layout.cshtml); fill them from each view, like the title, so inner pages don't all repeat the homepage's.

If the scan says preview services get different content, the cause is usually bot protection or a firewall that challenges unfamiliar visitors. In its settings, allow the link-preview services through, or ask your host to.

When a preview is out of date

Apps keep a copy of a preview once they have fetched it, so a changed picture may not show straight away. Ask them to fetch the page again: Meta's Sharing Debugger does this for Facebook, and LinkedIn's Post Inspector for LinkedIn. To check yours before anyone shares it, run the free scan, which reads the tags on the pages it visits and opens the share picture; the sample report shows the layout. The titles guide covers writing the title and description themselves.

Checklist

The homepage and each page people share have og:title, og:description, og:image and og:url.
The twitter:card tag is summary_large_image.
The share picture is 1200 by 630 pixels and well under 5 MB.
The picture's address is a full https address that opens, and robots.txt doesn't block it.
Preview services get the same page as a browser.
After changing a preview, you asked Facebook and LinkedIn to fetch it again.

What the free scan checks for this

These are the FocalScore checks that cover this guide's subject. Each one in your report says what it found, shows the evidence and gives the fix.

Open Graph / Twitter cards
Large social preview image
Social preview image is crawlable
Share previews on inner pages
Link previews get the same page you do
Your social preview image is small enough to share

Sources

Last checked October 2026. Documentation, settings and rules change; if one of these pages now says something different, it is right and this guide is out of date. Tell us at info@focalscore.com.