Using Markdown, how do I center an image and its caption?

Question

I want to end up with:

Hello there!

      
      This is an image

Hi!

Where the image and the text This is an image

Answer 1

With kramdown (used by githubpages)

{: style="text-align:center"}
That is, while there is value in the items on
the right, we value the items on the left more.

Or using the response from @(Steven Penny)

{:.mycenter}
That is, while there is value in the items on
the right, we value the items on the left more.