I will try that. This problem with captions was there a long time before the picture gallery plug-in, but it might be interfering with your suggestions above. A valid point.
However, I have now approached it from another perspective.
Have a look at this posting.
You will notice
1. I have a properly formatted caption formatted and placed under the image (exactly as I have specified in CSS).
2. The extensive description has been pulled automatically from the jpg metadata (as has the caption, which WP does not allow you do).
3. The Location (ex jpg metadata)
4. Copyright (ex jpg metadata).
I have not entered any of this data using WP editor or a replacement editor, but I have posted a single short code in a std WP posting. I manage my images in Lightroom, apply the metadata there. I have now an automated process to export from Lightroom . This is very close to what I have been striving at for months.
I have wasted 2 full days dealing with the WP caption mess. It is absolutely amazing that this problem exists with such themes as 2012.
I will go back later and explore the WP caption problem, but cannot afford to spend any time on it right now.
I really appreciate your help and will return to this, purely out of stubbornness to get to the bottom of it. I will post here when I crack it. HTML / CSS is not my scene and this is hard, frustrating work for me. Thanks yet again.