Each example file in help contains the image preview (stored in the "Thumbnails" zip directory of the ODF file).

I ran the below command in help directory (with only fr translation installed) :
find . -type f -not -iname '*.htm*' -not -iname '*.js' -not -iname '*.css' -not -iname '*.svg' -not -iname '*.png' -not -iname '*.xsl'

I got the below results :
./media/navigation/favicon.ico
./media/icon-themes/color_scheme/standard
./media/icon-themes/color_scheme/dark
./media/icon-themes/README.txt
./media/icon-themes/COPYING-ICONS
./media/files/scalc/pivot.ods
./media/files/scalc/conditionalformatting.ods
./media/files/scalc/functions_ifs.ods
./media/files/scalc/function_fourier.ods
./media/files/scalc/imtrigon.ods
./media/files/scalc/trigon.ods
./media/files/scalc/fr/pivot.ods
./media/files/scalc/fr/conditionalformatting.ods
./media/files/scalc/fr/functions_ifs.ods
./media/files/scalc/fr/function_fourier.ods
./media/files/scalc/fr/imtrigon.ods
./media/files/scalc/fr/trigon.ods

The "ods" files use 262 ko. Removing all image previews from them saves 122 ko.

When we remove the image previews in each of 119 translations, we could save up to 7344 ko of installed size.

This could reduce the size of the install archives to be installed on the host.