The og:image tag defines the thumbnail image that is shown when your website is shared on Facebook, Twitter (X) and different social platforms. It is important to use an image that is representative of your page and is likely to grab the attention of people scrolling through their feed.

Social Media og:image – open graph image
Recommended image size is 1200px X 630px

More context:
OpenGraph – Preview Social Media Share and Generate Metatags – OpenGraph
https://developers.facebook.com/docs/sharing/webmasters/
Image SEO – Screaming Frog