unwanted image captions

[Clint Adams <clint-8fiUuRrzOP0dnm+yROfE0A@public.gmane.org>]

Text::Markdown will render

    ![some text](https://example.org/img/onetwothree.jpg)

to

    <p><img src="https://example.org/img/onetwothree.jpg" alt="some text" /></p>

This is what I want and expect.

However, when transforming markdown to HTML with pandoc, the following
is produced:

    <div class="figure">
    <img src="https://example.org/img/onetwothree.jpg" alt="some text" />
    <p class="caption">some text</p>
    </div>

Is there a way to render the alt text but not a caption?  A quick look
at the source code suggests that there is not.