I've been reading up about the
figcaption elements for HTML5 over at the HTML5 Doctor and other places and thought I'd use these new elements to create captioned images in Drupal 7.
This is actually so easy its not funny, in fact you only need to make one configuration change to your image field and add one template override and you're done.
First - edit your image field settings and check the option to Enable Title field. We're going to re-use the title field to add our captions.