Fetches the page like a social crawler, parses Open Graph and Twitter Card tags, downloads the og:image and renders the actual Facebook and X cards.
About the Social Media Preview
The Social Media Preview fetches a URL exactly like the Facebook and X crawlers do — following redirects, reading Open Graph and Twitter Card tags with the platforms' real fallback rules — and then renders the actual cards: the Facebook link card (also what LinkedIn and WhatsApp show) and the X card in its correct summary or summary_large_image layout, including the title overlay X uses on large images.
It goes one step further than tag checkers: the declared og:image is downloaded server-side and verified — HTTP status, content type and real pixel dimensions — because an image tag that points to a broken, relative or undersized file is the most common reason shares render as bare links. Generate missing tags with the Meta Tag Generator and audit the full head with the Meta Tag Analyzer.
Almost always one of three things: no og:image tag, an og:image with a relative or broken URL, or an image below the platform minimum (200×200 px on Facebook, 300×157 px for X large cards). This tool fetches the declared image and reports its real dimensions and HTTP status.
1200×630 px is the safe universal size — it matches the 1.91:1 ratio both Facebook and X crop to for large cards, stays sharp on retina displays and is under both platforms' file-size limits (8 MB on Facebook, 5 MB on X).
Both platforms cache scraped previews aggressively. Force a refresh with the Facebook Sharing Debugger ("Scrape Again"); X refreshes its card cache automatically after roughly a week, or immediately when the URL changes (e.g. add a query parameter for testing).
X falls back to og:title, og:description and og:image — but only renders the large-image layout when twitter:card is set to summary_large_image. That single extra tag is the difference between a small thumbnail and a full-width card.
All of them read Open Graph: og:title, og:description and og:image cover practically every platform. WhatsApp additionally prefers images under 600 KB, and LinkedIn uses the same 1.91:1 crop as Facebook — so a preview that passes here will look right almost everywhere.