[NTG-context] Alternative width of figures in different documents (problem with modes?)

5 Feb 2013

      Hello ConTeXist.

I would like use modes alternative to change of image dimensions in 
different documents (presentation or print version).
Compilation in ConTeXt TeXLive 2012 version will compile without error, 
but without visual effect. Compilation with the standalone version 
fails. What is problem or eventually. how to solve my problem another way.

Thanks
Jaroslav Hajtmar

Here is my minimal example:

\enablemode[presentation]

\def\alternativewidth#1#2{
      \doifmodeelse{presentation}
          {width=#1}
          {width=#2}
}

\useexternalfigure[COW][cow.pdf][height=5cm, \alternativewidth{3cm}{5cm}]

\starttext

\input tufte

\placefigure[here,force][cowref]{Caption}{\externalfigure[COW]}

\input tufte

\stoptext