WordPress Salient theme: getting a full width 2 columns portfolio

The layout for those items looks like it’s using JS to set the width/position of the images, possible masonry/isotope.

You’d need to override the inline styles, like: (and I shudder to use important)

.col.span_3.element.one-fourths {
 width: 47.6% !important;
 position: relative !important;
 top: auto !important;
 left: auto !important;
}