Fill transparent areas with section background color

[BixFoot]

Is there a way to make the transparent areas of an image file fill with the section background color? Specifically, I want my banner images in my collections to do this on the Ride theme.

[BixFoot]

I guess what I'm asking is can I make these areas actually be transparent. I am getting a white fill in some of the transparent areas.

[BixFoot]

That would be amazing. Please help.