Yesterday I changed the main picture (and the preview) in the main page of my website. When I try to share it on Facebook, only the old picture appears. I deleted my web navigator data/cookies but the picture still isn't updated. Could you help me solve this problem please ?
Such a functionality is not handled by themes, I guess you are using Yoast so I'd recommend that you check out the plugin documentation: https://yoast.com/help/why-doesnt-facebook-display-an-image/