I entered this in global css
body {
background: url(../img/back.jpg) center center;
}
font-family: Arial, Helvetica, sans-serif;
font-size: 13px;
line-height: 1.42857;
color: #777777;
background-color: white; }
I still have the same plain white background, I thought maybe I needed to remove the background-color white making it none and still nothing.
I put the image titled back.jpg /public_html/themes/default-bootstrap/img