Background image for media screen not displaying whole image

I'm trying to make my site responsive and I cannot get my pages background image that covers 85% of the screen to display the entire image. It just shows a very small portion of it. What am I doing wrong? If it helps, my site is sundayfundayleague.com .

I'm attempting to do this..

.indexgraypage {
    width: 100%;
    left: 0;
    right: 0;
    min-height: 100%;
}
.homeimg {
    background-image: url("/images/bright_lights_smallest.jpg");
    width: 80%;
    background-size: cover;
    background-position: center;
    height: 100%;
    margin: auto;
    position: absolute;
    margin-right: 10%;
    margin-left: 10%;
}

via Chebli Mohamed