resolution 1920x1080 via $X11VNC_CREATE_GEOM

Dockerfile

@@ -9,4 +9,5 @@ RUN useradd --create-home vnc
 COPY --chown=vnc xinitrc /home/vnc/.xinitrc
 USER vnc
 EXPOSE 5900/tcp
+ENV X11VNC_CREATE_GEOM 1920x1080
 CMD ["x11vnc", "-create", "-nopw", "-no6"]