Some time ago LibreOffice changed thumbnail quality and now they are ~80-90% of my spreadsheets size. I searched in options but there is nothing to disable saving them. I didn’t search in expert configuration, because there is no search function there…I wonder why someone didn’t thought of adding search like in firefox about:config
Bug 61320 - FILESAVE, PREFERENCES: Allow user to choose whether to create thumbnails
Status: RESOLVED FIXED
libreoffice/core/commit · fdo61320: Allow user to choose whether to create thumbnails inside odf.
Tools → Options… → LibreOffice → Advanced → Expert Configuration:
(double click toggles value to false)
See also: Bug 73806 - Expert Configuration button opens huge and not resizable table
Status: RESOLVED FIXED
Thanks, great answer. Too bad it’s in nightly build, guess I have to wait 
That enhancement will be available in LibreOffice 4.3.0.
I have tested it successfully with LibreOffice 4.3.0 RC2.
That’s great news Thank you
I can confirm that it is available in 4.3.0 and it works