Can I set background image and opacity in the same property?

Question

I can see in CSS references how to set image transparency and how to set a background image. But how can I combine these two in order to set a transparent background image?<

Answer 1

I just added position=absolute,top=0,width=100% in the #main and set the opacity value to the #background

#main{height:100%;position:absolute; top:0;width:100%}
#background{//same height as main;background-image:url(image URL);opacity:0.2}

I applied the background to a div before the main.