The Link Previews extension allows notes to include information about hyperlinks in the note's content. The information may be obtained in any way, but most likely via Open Graph tags and other similar metadata.
style: “text” if imageUrl is not presentstyle: “text” if imageUrl is presentsiteName would be the domain name of the url{ "type": "note", ... "extensions": {"https://pawpub.entities.org.uk/extension/link-previews": [ { "url": "https://example.com/whatever", "siteName": "Example website", "title": "Whatever page!!", "description": "This is a description for the page", "style": "largeImage", // or smallImage or text "imageUrl": "https://example.com/whatever/preview.png" }, ... ]} }