Markdown style says the format for pictures is:
![your text] (url)
However, when using this format, you now see:
![your text] (

)
*I put the space between the "]" and "(" symbols in this issue, but not in the steemit editor.
Please make sure that you are using "raw" mode, not editor when willing to use markdown.
I observed that above can happen when you use markdown in editor:

and switch to raw mode. This would change code to:
<html>
<p></p>
</html>
In this case removing html might help
If need, it should be tracked in https://github.com/steemit/steemit.com/issues.
It's most likely the issue described by @Gandalf-the-Grey.
If not, please file here instead: https://github.com/steemit/steemit.com/issues
Removing the html did help. Thanks all!