Following up on a previous question of mine, I would like to know how to remove the large thumbnail from .odt files created in LibreOffice. I don’t find this feature useful at all; Trisquel doesn’t display them, and when I used Windows it didn’t identify the document well enough.
When I rename the .odt file to a .zip archive, extract its contents, delete either the thumbnail or the folder that contains it, and recompile the file (or whatever the proper term for that is) the resulting ODT is irreparably corrupted.