Please, excuse that this is not even an started poject. I will be updating what I found about the process.
I'm researching how to do this work. I will use some parts of Cardiolizer, other repo of mine. Maybe I should make some kind of shared library.
#This is how it works
soffice --headless --convert-to odt --outdir documents/ *.dochttps://cgit.freedesktop.org/libreoffice/core/tree/filter/source/config/fragments/filters
This at the end of page-layout-properties <style:background-image xlink:href="Pictures/escopia.png" xlink:type="simple" xlink:actuate="onLoad"/>
And this on the manifest.xml <manifest:file-entry manifest:media-type="image/png" manifest:full-path="Pictures/escopia.png"/>