niallkennedy/twitter-cards — pull request #7 by niallkennedy (2013-03-17 17:06:32+00:00)
Title: auto generate photo card for image post formats

If post format is image and post thumbnail exists and that thumbnail meets the minimum width and height requirements of a [Twitter photo card](https://dev.twitter.com/docs/cards#photo-card "Twitter Cards photo card documentation") then switch to a card type of photo.

Assumption your 279x149px image content would be better highlighted as a Twitter summary card than fail the Twitter photo card requirements.