Ask Your Question

Revision history [back]

horst's answer is the correct one. Please vote for his, and do not vote for this one, which is just a concise summary of the method.

To remove a thumbnail from a .odt file generated in LibreOffice, and drastically reduce that file's size (by about 18 kb, depending on the file):

  1. Finish editing the file! As soon as you save it in LibreOffice, the thumbnail will be recreated and you will have to repeat this process.
  2. Right- or context-click on the file and select "rename". Change the file extension to .zip. (On Windows 7, you may need to show the file extension to rename it, so open the Start menu, search for "Folder options" and open the result of that name, click the "View" tab, and uncheck "Hide extensions for known file types".)
  3. Open the files in the .zip archive with an archive manager of your choice. If you're using Windows, you may be able to use the plain file manager, but you might have to install the free and open-source program 7-Zip if you can't open .zip files. I'm fairly sure that Mac OS and most Linux distributions ship with decompression software. Do not extract the folder's contents.
  4. You should see several files and folders, the source code of the .odt file. Open the folder called "META-INF" and you will see a file called "manifest.xml".
  5. Open this file with a plain text editor of your choice and delete the line that says <manifest:file-entry manifest:full-path="Thumbnails/thumbnail.png" manifest:media-type="image/png">.
  6. Return to the main folder of the extracted archive and delete the folder called "Thumbnails".
  7. Close the archive manager. Rename the file's extension to .odt as in step 2. Observe how its size has been drastically reduced.