pandoc/test/command/3450.md

% pandoc -fmarkdown-implicit_figures
![image](lalune.jpg){height=2em}
^D
<p><img src="lalune.jpg" style="height:2em" alt="image" /></p>

% pandoc -fmarkdown-implicit_figures -t latex
![image](lalune.jpg){height=2em}
^D
\includegraphics[width=\linewidth,height=2em,keepaspectratio,alt={image}]{lalune.jpg}