A General Strategy for Images with Captions in Content
Your desire for a "non-Javascript" solution is in conflict with your desire to allow users to "see" the image in their WYSIWYG editor, as you need to run Javascript for those to work.  So, you'll have to either drop the "non-Javascript" requirement, or be satisfied with image fields that may appear above or below the main body.  [Note 1: Images "above" the node body can be set to float left or float right, and thereby appear to be inside the text.  Note 2: If by "non-Javascript" you mean non-JS at render time, then no problem.]

Whichever way you go -- be it images embedded in a WYSIWYG editor, or images as file fields, you'll probably want to use the media module, as it can support either method.

There is a lot of information available on the media module, which is becoming "the way" to do images in Drupal.  Many additional contrib modules are compatible with media. You'll want to take a look at the following two configuration guides:

Media 2.0 Quickstart

Configuring embedded images with media and wysiwyg modules

Here is the point where I remember to take a step back and point out that my experience is with media 2.0-unstable7.  Depending on how comfortable you are with making adjustments to php code, you might prefer to use the stable release, which is currently 7.x-1.2.  I didn't have too much trouble with 2.0-unstable7, except for the fact that it does not support editing of arbitrary image metadata on WYSIWYG images, so I am using only image file fields at the moment.  If the only metadata you wish to attach to your images is a caption, then I expect that 7.x-1.2 should work for you, although I have not tried it myself.

In any event, I would recommend using the provided "title" field, and render that as a caption. Doing that is as easy as visiting admin/structure/file-types and clicking on "manage display" for the image file type.  This page works just like the "manage display" page in cck; you can just drag the "title" field up so that it is under the "file" field, and use css to style it as a caption.  You'll probably also want to download and enable the entity_view_mode module, which will allow you to define additional view modes for your image files.

As I said, I'm not embedding images in WYSIWYG editors at the moment, but the article you quoted gives good advice on that.  If you're using the media module, you should still be able to format the title field as a caption regardless of whether you're using file fields or WYSIWYG.