Relative image link doesn't render in overview

My project contains a readme and an image. The readme refers to the image using relative link syntax.

#!markdown

![A drawing of a conch shell](Conch_drawing.jpg)

After I click Edit on the readme, and before the editor loads, I briefly see the rendered document, and it includes the image.

https://bitbucket.org/isme/conssh/src/master/README.md?mode=edit&spa=0&fileviewer=file-view-default

When I am simply viewing the readme or the project overview, the document renders with the alternate text instead.

https://bitbucket.org/isme/conssh/src/master/

In the viewing mode I was expecting the same result as in the editor mode.