Theme Curtana has full Open Graph and Twitter Cards support.
It will look for the image in the following order:
- Use 
page.thumbnailif defined in your post front-matter field. - If no specified 
page.thumbnaildefined, it uses Heading Background Image (aka.page.heading-bg) if defined in your post front-matter field. - If no heading background image found, Curtana will try to grab the first image (wrapped inside 
<img>) in your post as your post thumbnail - If nothing found, it falls back to 
logo.pnglocated at your site root. 
You can always use page.thumb_force_logo in your post’s front-matter field to override the above lookup.
Here’s a preview on Twitter:
