A Twitter Image App Card is a type of App Card that makes the image in the promoting app more proficient, so the card looks a bit different than a Basic App Card.
Otherwise, the requirements and specification are the same as with Basic App Card (taken from Twitter):
- Tweet copy: 116 characters are available (24 characters are used for images).
- Image size: 800 x 320 pixels (max 3mb).
- File types: PNG and JPEG are recommended. We do not accept BMP or TIFF files.
- Title/price: Pulled from app store.
- Call to action options: Install (default if app is not installed), Open (default if app is installed), Play, Shop, Book, Connect, and Order.