GP Slovenia is working on this page:
https://act.greenpeace.org/page/38777/petition/1?mode=DEMO

They are asking if we can set the level of transparency for background image. "We would like it more visual as it is (blocks more transparent) and I found nothing easily adjustable in the HTML."

I think it would be great if we could put something editable in the html header where users can play with the background image transparency a bit. Would that be possible? This would also be very useful for GPI petitions and other NRO's using the P4 template in EN. Thanks!