Add an image overlaying a portion of the Soliloquy slider

soliloquy-slider-image-overlay.css

.soliloquy-container .soliloquy-slider:before {
    display: block;
    content: '';
    width: 50%;
    height: 100%;
    position: fixed;
    right: 0;
    z-index: 9;
    background: url('http://www.360fashion.net/wp-content/uploads/2013/01/image-placeholder-500x500.jpg');
    background-size: contain;
    background-repeat: no-repeat;
    background-position: right center;
}