Getting the image right
Use a JPG or PNG at 1200 × 630 pixels, a 1.91:1 shape, and keep it under about 5 MB. Smaller images can show as a small thumbnail instead of a large card, and other shapes get cropped.
Keep the important parts, like text and faces, away from the edges, because some apps crop to a square. The address must be public and absolute, starting with https://, not a path like /images/card.png.
Why an old preview still shows
Apps save a copy of each link's preview, sometimes for days or weeks, so a fix won't show up straight away for a link that's already been shared.
Most big apps have a tool to refresh it: Facebook's Sharing Debugger and LinkedIn's Post Inspector both fetch the page again. Elsewhere, adding something harmless to the link, like ?v=2, makes the app treat it as new.
Frequently asked questions
How do I check a website's Open Graph tags?
Paste the page's link above and press Check link. You'll see every og: tag we found, previews of the share card, and a list of what's missing or too long.
What size should an og:image be?
1200 × 630 pixels, a 1.91:1 shape. That shows as a large card almost everywhere and stays sharp on high-resolution screens.
Why isn't my link preview showing an image?
Usually there's no og:image tag, the image address is a relative path or http://, the file is too big, or the image is blocked from public access. The checker tells you which.
How do I update a link preview after changing it?
Apps cache previews. Use Facebook's Sharing Debugger or LinkedIn's Post Inspector to fetch the page again, or share the link with ?v=2 added to the end.
Do I need Twitter card tags as well as Open Graph?
Add twitter:card set to summary_large_image. For the title, description and image, X reads your og: tags if there are no twitter: ones.
Does this checker store the pages I check?
No. Our server reads the page's tags, sends back only those, and keeps nothing. It only checks public web pages.