Here’s the way to remove border from image used in slider…
Just add next 5 lines bellow in Custom CSS field:
.sliderpost_featured_image img {
-moz-box-shadow: 0 0 5px #fff;
-webkit-box-shadow: 0 0 5px #fff;
box-shadow: 0 0 5px #fff;
}
It tooks couple hours to discover the right lines!