Support a new "summary" OpenGraph preview card type (or respect the Twitter/X standard)

[lylo]

When you add a link to a Bluesky post, a preview "card" is created. This works great when the OpenGraph image is a photo or a dedicated large image.

However, when you link to a blog post which has no image, that site's generic OpenGraph image is used which often doesn't look great. Here's an example:

The current behaviour of Bluesky is the same as the Twitter "summary_large_image" card type. It would be great if there was an option of a "summary" card which rendered a small image in a more compact format. Example:

Details of Twitter cards can be found here:

https://developer.x.com/en/docs/x-for-websites/cards/overview/abouts-cards

The suggested behaviour could be achieved by respecting existing Twitter meta tags (https://developer.x.com/en/docs/x-for-websites/cards/overview/markup) or by creating a new card type for Bluesky.