Problem
This code,

renders correctly in preview as an embedded image. But after posting it no longer renders correctly. Instead it renders as a text fragment:
wrong on the Internet.”">
Demonstration
Open the this post in the editor and see how the following code renders in the preview:

Workaround
Avoid the underline character. This code renders correctly after posting:

Discussion
I suppose underlines in the image description are mistaken for Markdown. In the image description they really should be taken as literals (or at least ignored); regardless, they should not cause the sort of rendering error shown above.