Getting Picture Captions

I'm looking for the best way to get captions for the images that are inside the news feeds.  I have tried cachign the images in the photo feed, but it seems like that rarely match the images that are appearing in the articles.  Could the caption be included with the image in the article feed, or maybe a web service could be created that we could use to get the caption for a specific image (or array of images to get all the image in an article at once)?  A simple REST service where we pass picture ids could handle this quite easily I would think.

Just my thoughts.  Please let me know if anyone has come up with a good way.