You probably know about combinations to place images side by side: \startcombination[3*1] {\externalfigure[cow]}{cow} {\externalfigure[mill]}{mill} {\externalfigure[hacker]}{hacker} \stopcombination Now, the widths aren’t calculated automatically. You could define them on your own: \startcombination[3*1] {\externalfigure[cow] [width=.3\textwidth]}{cow} {\externalfigure[mill] [width=.3\textwidth]}{mill} {\externalfigure[hacker][width=.3\textwidth]}{hacker} \stopcombination But that’s ugly and tedious. Hans did it for you: \definemeasure[combination][ (\textwidth -\effectiveleftskip -\effectiverightskip -\numexpr\combinationparameter\nx-\plusone\relax\dimexpr\combinationparameter\distance\relax )/\combinationparameter] So you can say: \startcombination[3*1] {\externalfigure[cow] [width=\measure{combination}]}{cow} {\externalfigure[mill] [width=\measure{combination}]}{mill} {\externalfigure[hacker][width=\measure{combination}]}{hacker} \stopcombination But that’s still tedious. With the power of \defineexternalfigure: \defineexternalfigure[combination][width=\measure{combination}] (That’s predefined, no need to copy!) \startcombination[3*1] {\externalfigure[cow] [combination]}{cow} {\externalfigure[mill] [combination]}{mill} {\externalfigure[hacker][combination]}{hacker} \stopcombination Beautiful. ;) Have fun, Hraban