adjust background for images in docs
adjust background for images in docs

kalxas/pycsw,geopython/pycsw,bukun/pycsw,kalxas/pycsw,ricardogsilva/pycsw,kalxas/pycsw,tomkralidis/pycsw,tomkralidis/pycsw,bukun/pycsw,tomkralidis/pycsw,geopython/pycsw,bukun/pycsw,ricardogsilva/pycsw,geopython/pycsw,ricardogsilva/pycsw