"There are 7 Card types that can be attached to Tweets, each of which has a beautiful consumption experience built for Twitter's web and mobile clients:
Summary Card: Default Card, including a title, description, thumbnail, and Twitter account attribution.
Summary Card with Large Image: Similar to a Summary Card, but offers the ability to prominently feature an image.
Photo Card: A Tweet sized photo Card.
Gallery Card: A Tweet Card geared toward highlighting a collection of photos.
App Card: A Tweet Card for providing a profile of an application.
Player Card: A Tweet sized video/audio/media player Card.
Product Card: A Tweet Card to better represent product content."
