When you share a link to a page on social networks like Facebook a thumbnail is displayed to represent your page. You can customize this image with WebStarts by following these steps.
Step 1. Create an image you’d like to be displayed when sharing a link to your webpage on Facebook or another social network.
Step 2. Login to your WebStarts account and choose to edit the page you’d like to add a customized thumbnail to.
Step 3. Click on File > Page Settings > Upload Site Thumbnail.
Step 4. Click on the button labeled “Upload Thumbnail” and choose the image you’d like to use for your thumbnail from your local computer.
Step 5. Save your changes and share your link on Facebook to see your custom thumbnail.