Question 1

What are Open Graph tags?

Accepted Answer

Meta tags in a page's <head> (og:title, og:description, og:image, og:url, og:type) that social sites and chat apps read to build the card shown when someone shares the link. X also reads its own twitter: tags and falls back to Open Graph.

Question 2

What size should og:image be?

Accepted Answer

1200×630 pixels (a 1.91:1 ratio), as a PNG or JPEG under 5 MB, at a full https:// URL. Smaller images still work but often show as a small thumbnail instead of a large card.

Question 3

I fixed my tags but the old preview still shows. Why?

Accepted Answer

Every site caches previews. LinkedIn has a Post Inspector and Facebook a Sharing Debugger that refresh their cache; X and Slack refresh on their own, usually within a day. Adding a query string (?v=2) to the shared link also forces a fresh read.

Question 4

Why does the checker say the site blocked the request?

Accepted Answer

Some sites rate-limit or challenge automated requests. Social sites use their own crawlers, which those sites usually allow, so the real preview may still work. Try another page of the same site.

Question 5

What does the checker fetch?

Accepted Answer

Only the page you enter and the image its og:image tag points to, as SortLift-User, and only if the site's robots.txt allows it. Nothing is stored.

Link preview checker

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