So far we have only experimented with MIX (http://www.loc.gov/standards/mix/
) which is a rather technical Niso standard. It encodes all things about the image file someone might want to know but does not provide fields for the description of the content. There are other minor problems with it, but it is relatively new and there is still space to grow.
In order to package everything neatly together it seems we have to use METS (http://www.loc.gov/standards/mets/
). We haven't implemented it yet, but it is high on my agenda for this autumn, since we have accumulated a lot of scans of woodblock prints, and want to combine them with full-text and translations TEI files.
It allows to combine pointers to your various image files, TEI description and MIX techdata into one intelligible whole. The idea is to package various digital objects together to give digital librarians a handle. Last time I looked METS files can include complete TEI headers and MIX files. In that case it will be difficult to validate the package completely, but with NVDL even that might be possible now. And using already existing metadata chunks makes good sense.
I would be interested in hearing from anyone who has used METS to archive projects which involved a TEI text.