DocX
convert -verbose -quality 100 -fill "rgba(255,255,255,1.00)" -density 300 -alpha off test.docx test_docx.png
convert -verbose -quality 100 -fill "rgba(255,255,255,1.00)" -density 300 -alpha off test.pdf test_pdf.png
ODT
convert -verbose -quality 100 -fill "rgba(255,255,255,1.00)" -density 300 -alpha off test.odt test_odt.png