Open Graph (OG) is a metadata protocol that helps services build a preview card when a page link is shared. On Joomla sites, a template or extension usually adds these properties to the HTML document’s head.
Main properties
og:title supplies a title, og:type identifies the object type, og:image supplies a representative image URL and og:url identifies the object’s permanent address. Additional properties include og:description, og:site_name, og:locale and image dimensions and alternative text.
Use complete absolute URLs for the page and image. The receiving service must be able to retrieve them without authentication. An article page typically uses article, while a general website page can use website.
Other metadata
OG does not replace the normal title, meta description, canonical declaration or Schema.org structured data. Each has a different purpose. Sharing services apply their own display rules, so tags do not guarantee identical previews everywhere.
Configuration in Joomla
Establish which part of Joomla generates the tags: the template, an SEO plugin or the component. Multiple sources can produce conflicting duplicates. On multilingual Joomla websites, the title, description and URL should match the current language version.
Inspect the public page’s final HTML rather than only administrator fields. An outdated preview may come from the sharing service’s cache. Also confirm that its crawler can retrieve the intended image in a supported format.
Summary
Open Graph helps control how a Joomla page link is presented. Preview quality depends on consistent metadata, accessible resources and the receiving service’s processing.