How can I take pic.twitter.com URL and get the thumbnail URL for that photo?
Sometimes I see old-style retweets that include a link to a status with a Twitter-hosted image, like this: "Check this out RT @username: Check out this pic: pic.twitter.com/TnVqD7CB". I want to get the thumbnail of that image, but because the photo wasn't embedded in the old-style retweet, it doesn't appear in the tweet's entities.
Off the top of my head, all I can think of is this:
1) Expand that short URL (using curl?) to get the original tweet's URL
2) Extract the status ID from the tweet URL (using a regular expression)
3) Call statuses/show to get the tweet and therefore its entities
That seems a bit convoluted; is there a more direct method?