When it comes to changing the link image thumbnails it depends on each social platform. We'll examine each below.
Facebook. You can customize thumbnails only for verified domains. To verify a domain please follow the instructions on the link. After domain verification, all the links shared from a verified domain that are attached to the business page are editable in Planable.
Linkedin. Thumbnail previews for Linkedin are fully customizable. To edit an image just click the photo icon in the top left corner of the thumbnail. To edit the title or description click on the text below.
Twitter. Twitter link thumbnails (or cards) are not customizable and they are generated from Twitter specific meta tags that are set on the website. If you are the owner of the website you can learn how to add tags right here.