When you share your page, Facebook and Twitter will show a screenshot of your page without you having to do anything extra. This is achieved using a little screenshot app I created as a separate project.
(Side note: For now I only use it for the Alignment project, but I might turn it into its own thing with proper API. Or you can just remix it and make your own.)
This way, you have two versions of your page:
The image version is what's used for the social media thumbnail. Neat!
And here's one way you can use this project:
Tag your bot! https://t.co/84CibXmFJw— Botwiki (@botwikidotorg) August 25, 2017