It looks like Twitter changed the image thumbnail size to a smaller size on the photo card after the large_image_summary card release came out in the last few weeks.
The image that shows up in the live Twitter feed is much smaller than previous photo cards size and the new large_image_summary. This images are much smaller that the version shown on the dev validator https://dev.twitter.com/docs/cards/validation/validator tester.
Is there a way to get the images on live Twitter to be the same larger size they are in the validator preview and previously shown? I looks like margins have been set very large on 3rd party cards displays.