Hi, Thanks for the quick responses.
The \externalfigure commands passes the values of the width/height keys to Lua which can’t handle relative values [...] to convert a relative (e.g. \textwidth) in a absolute value (e.g. 12pt) you can use the \dimexpr command.
\externalfigure[…][width=\the\dimexpr.3\textwidth\relax]
I'm seem to be not educated enough about dos and don'ts: To me it seemed mandatory to use relative sizes as I might have to change the layout of my document (*). So, do I get it right that the idea of this change is to stick to a rigid A4 setting (i.e. all figures are e.g. of width 5 cm) and then simply change the print out size to A5: \setuppapersize[A4][A5] A quick "yes, keep it rigid" or "no, do it adaptively" would be enough to get me on track (in case I am not telling bull****). I'll adapt my doc accordingly. Cheers, Andreas (*) I am currently working on a document, which Iis going through assessment in A4 and very likely published in A5