Images are cut off by circular border in "Home Feature" area

It looks like there is some sort of circular halo cutting off my images in the Home Feature area. I cannot find a setting or CSS value to get rid of it. Even when I try to change the value to something smaller, the invisible circular border remains.

Look on http://www.webplumb.com/ to see what I mean.

What do I do to get rid of this effect? I want my icons to show without the circular border.

 

I found some icons that fit within the circle (they themselves are circular). Would be great to learn how to remove the circle if desired.

 

Hi,

Please paste the code given below in Custom CSS section
(Appearance -> Theme Options -> Styling Options -> Custom CSS) of your dashboard.

Code:

#site_features .f-content img {
border-radius: 0;
}

Thanks,
Praveen