--snapshot filename
       Create  a  snapshot image from the specified layers and save it to filename. The snapshot is saved
       in PNG format.

--lang language
       Set the language used by QGIS. Language is specified using the locale string that matches  one  of
       the translations supported by QGIS. For example, to use the German translation, specify --lang de

--project filename
       Load  the  specified  QGIS  project file. The layers specified in the project file are loaded, the
       layers are symbolized, and the view extent is restored.

--extent xmin,ymin,xmax,ymax
       Set initial map extent by passing coordinates of that rectangle.

--help
       Display brief usage help.