body {
    margin: 0 auto;
    background: rgb(255,255,255);
}

.content {
    width: 1000px;
    height: 2000px;
    margin: 0 auto;
    background: rgba(10,10,200);
}

img.prev {
    width: 250px;
    float: left;
    border: 1px solid rgba(0,0,0,0.5);
    border-radius: 3px;
    margin-right: 15px;
}