Unoconv is a shell command that utilizes LibreOffice/OpenOffice and supports all formats it can read as import and all formats it supports exporting to. It does export both to PDF and several image formats so if you are unable to get it to export the first page as image you can use it to create a PDF and use Imagemagick to do the rest.
It's in the repositories of the most common distros and since it's python it's probably possible to install it on a windows machine too with some efforts.