How should a shared link preview be represented in forum markup?

Definition: In Google’s discussion forum structured data, represent a link shared in a post or comment as a WebPage object inside sharedContent. Put the preview image on that WebPage, while the post or comment’s image property describes an image shown inline in that contribution.

Key facts

• Google’s DiscussionForumPosting documentation is for forum-style sites where people collectively share first-hand perspectives.
• The same documentation defines sharedContent as the primary shared content in a post and lists four accepted types.
• For a shared URL, Google describes WebPage as the common sharedContent type and gives an example containing the external URL.
• Google assigns inline images to the post or comment’s image property. A link-preview image belongs in the image property of the attached WebPage inside sharedContent.
• Schema.org describes sharedContent as a CreativeWork such as an image, video, or audio clip shared as part of a posting, and describes a WebPage image as a URL or a fully described ImageObject.

What belongs in sharedContent?

Google defines sharedContent as the primary shared content in the post, when applicable. It accepts WebPage, ImageObject, VideoObject, and DiscussionForumPosting or Comment. The WebPage choice is the documented pattern when the post shares a URL for a topical discussion.

The page’s example uses a WebPage object whose url identifies the shared page:

"sharedContent": { "@type": "WebPage", "url": "https://example.com/external-url" }

A shared link therefore gets its own nested creative work. The forum post remains the DiscussionForumPosting or Comment, and the nested object describes the page being shared.

Where does the preview image go?

Google’s field guidance says that image on a post represents any inline images within that post. When the image is a link preview, the documentation places it in the image field of the attached WebPage in sharedContent. The same rule appears in the Comment properties: an image displayed as a link preview is part of the attached page, rather than the comment’s inline-image field.

The two roles can be represented together like this:

{
  "@type": "DiscussionForumPosting",
  "image": "https://example.com/inline-photo.jpg",
  "sharedContent": {
    "@type": "WebPage",
    "url": "https://example.com/external-url",
    "image": "https://example.com/link-preview.jpg"
  }
}

The Schema.org WebPage definition describes image as an image of the item and allows either a URL or a fully described ImageObject. Google also says to omit default, icon, placeholder, and author images from the post’s image field when the post has no inline images.

Which shared content type fits the post?

The content’s role determines the nested type. Use WebPage for a shared URL. Use ImageObject when the primary content of the post is an image, and VideoObject when it is a video. A quoted or reposted forum contribution is represented with DiscussionForumPosting or Comment in sharedContent. These choices describe the primary shared item, while an ordinary photograph placed in the body remains an inline image.

Schema.org’s definition of sharedContent covers a CreativeWork shared as part of a posting, including an image, video, or audio clip. Google’s forum documentation supplies the more specific four-type set for this markup and includes the URL example for WebPage.

How can the markup be checked?

Google’s implementation workflow says to validate the code with the Rich Results Test and fix critical errors. It also directs site owners to deploy a few pages containing the structured data and use the URL Inspection tool to test how Google sees the page. The page must be accessible to Google and cannot be blocked by a robots.txt rule, a noindex tag, or login requirements. After deployment, Google recommends the Rich result status report for finding issues once pages have been indexed.

Related terms

• When should a forum use DiscussionForumPosting instead of Article?
• Which content fields are required for a forum post?
• WebPage structured data
• Must images referenced in structured data be indexable?

FAQ

Should the post’s image property contain the link preview?

No. Put a link-preview image in the image property of the nested WebPage under sharedContent; reserve the post or comment’s image property for an inline image.

Which type describes a post whose primary content is an image?

Use ImageObject as the sharedContent type. Google lists ImageObject for a post whose primary content is an image.

Can the nested WebPage use an image URL?

Yes. Schema.org allows the image property to be a URL or a fully described ImageObject.

What type describes a quoted forum contribution?

Use DiscussionForumPosting or Comment in sharedContent, as appropriate to the referenced contribution.

Sources

1. Google Search Central, "Discussion forum (DiscussionForumPosting) structured data", 8 September 2026
2. Schema.org, "sharedContent - Schema.org Property", undated
3. Schema.org, "WebPage - Schema.org Type", undated

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