```
% pandoc -f latex -t native
\newcommand{\mycolor}{red}
\includegraphics[width=17cm]{\mycolor /header}
Magnificent \mycolor{} header.
^D
[ Para
[ Image
( "" , [] , [ ( "width" , "17cm" ) ] )
[ Str "image" ]
( "red/header" , "" )
, SoftBreak
, Str "Magnificent"
, Space
, Str "red"
, Str "header."
]