The default theme already adds a /.../card/ endpoint which you can use to manually create an image (preview or publish, add /card/ to a post's URL, screenshot the node, go back and edit the post, upload the screenshot). It would be much, much nicer if that whole process was done for you, i.e. if you haven't set an image on the post, the default theme generates the image for you and includes it in the post's meta tags.
The default theme already adds a
/.../card/endpoint which you can use to manually create an image (preview or publish, add/card/to a post's URL, screenshot the node, go back and edit the post, upload the screenshot). It would be much, much nicer if that whole process was done for you, i.e. if you haven't set an image on the post, the default theme generates the image for you and includes it in the post's meta tags.