When you share a link on Facebook or Twitter, a preview of the content is available. This is a great way to drive back traffic to your website.
The content actually has a cache, so if you change an element of the link, such as a featured image, excerpt or title, it may not change in the social preview. There is a way to manually update the social card.
Go to Facebook’s developer tools, past the url you would like to update and click “fetch new scrape information.”
If you already have a post on Facebook, you can also update the link preview on a post by clicking on the time of the post. This will make the post fullscreen. In the upper right hand corner, click the arrow, then click “refresh share attachment.” You may need to repeat these steps several times until the post refreshes.
Go to Twitter’s card validator, past the url you would like to update and click “preview card.” This should also update any links in previous tweets.