minor readme update

README.md

@@ -130,18 +130,9 @@ Add a webring with a shortcode:
 ### Extra Data
 
 - Set the `author` in both the main config and in pages metadata.
-- Use the `image` variable in pages to add an image to HTML `<meta>` tags.
 - Similarly, set `favicon` in the main config, and it will be used as the site icon.
 - Set `footer_content_license` and `footer_content_license_link` if you wish to display content license information in the footer.
 
-#### Disable Twitter Card
-
-Twitter metatags are generated by default. To disable them, set `extra.twitter_card` to `false` in `config.toml`:
-
-```toml
-[extra]
-twitter_card = true
-```
 
 ### License