What Open Graph tags are
Open Graph is a set of tags in your page’s HTML that tells chat apps and social networks what to show when someone shares your link. The Open Graph protocol defines them. Most apps need four:
og:title: the title on the card, usually your page title without the site name.og:description: one or two sentences about the page.og:image: the picture, as a fullhttps://address.og:url: the page’s own address on your main domain.
The right image
Use an image of 1200 × 630 pixels with your app’s name and what it does, on your own domain. Keep the important part in the middle, because some apps crop the edges. If the preview still shows your builder’s default picture, your builder’s image tag is still in place.
Why an old preview keeps showing
Apps keep a copy of each preview. After you fix your tags, LinkedIn’s Post Inspector and Facebook’s Sharing Debugger refresh it on request. Other apps update on their own schedule.