Convert emf to PNG image using command line
(Found in https://stackoverflow.com/a/28749719)
Use LibreOffice:
libreoffice --headless --convert-to png image.emf
The other answers here did not work for me, but one I found on stakoverflow did
Another way is to use inkscape:
inkscape -e file.png source.emf
See inkscape --help for more export options (area to export, dpi, image resolution, background color etc).
According to this page: http://www.imagemagick.org/script/formats.php
EMF R Microsoft Enhanced Metafile (32-bit) Only available under Microsoft Windows.
Source