This article just talked about what Drupal does out of the box with
images. A simple way to manage captions for an image field would be to
add a field. then you could display them together. And that would work
with the core set of modules.
However, if you have multiple images and multiple captions within
an article, then you will want to turn to a contributed module.
A lightweight solution is this jQuery module - jCaption - which
turns the "alt" or "title" attribute into a caption.http://drupal.org/project/jc
More information about text formats