If you have recently changed your logo and try to share a link of your website on Facebook, it’s possible that Facebook display your previous logo.
Visit Facebook’s Debugger site, enter the URL you want to share on Facebook and click the Debug button.
The Debugger will display the settings that Facebook currently has cached for your site. To refresh this data, click the ‘Fetch new scrape information’ button at the top of the page. You should now see the correct content for your website on the Debugger page. The link to your website is now ready for sharing.
More you can check here https://developers.facebook.com/docs/sharing/webmasters/images/