I asked:
(4) Where can I put personal files that I would like context to use regularly.
which Marco kindly answered:
In the directory TEXMFHOME points to or texmf-local.
This works for my personal file env_letter.tex which is called with \environment env_letter.tex. This file env_letter.tex calls the letter module, sets some correspondenceparameters, etc. But env_letter.tex calls two pdf files with \externalfigure (see below). These two pdf files are also in the directory pointed to by TEXMFHOME but they show up in the finished document as gray "state: unknown" boxes Does this involve "tracking" as discussed in http://wiki.contextgarden.net/Command/externalfigure ? Thank you very much for guidance. best, Michael % Define logo for the first page header \defineletterelement[layer][head][example]{% \framed[background=logohead,frame=off,align=left]{% \externalfigure[UMA_Seal_200_Maroon.pdf][height=3.1cm]} } \setupletter[ signature={\externalfigure[signature-blue.pdf]} ]