Thanks Simon.  So...a few things... 1.  If I edit the css in the browser manually for the images as they are embedded in my html, the css you've given doesn't want to center my images.  Only the centering css I note in my original post wants to work. 

2. Yes a graphic component would be better in terms of putting images into my content, however, per another thread my requirements are fairly unique.  The course I've been tasked with putting into an LMS has been written in markdown.  I want to keep the core content in markdown and with a bit of tom-foolery output it into different formats.  Exactly what I'm doing is documented here.  Another challenge with the graphic component is that I can't quite figure out how to get it to work with multiple images in my case - it seems to be geared to only work in a very specific circumstance, such as your material having only 1 image and the text can only be placed above it.  I have several images and I need text above and below it.

My approach could be wrong...I'm open to changing it.  I'm piecing all this together a bit at a time...thanks for replying.