#blocGen {
    max-width: 890px;
    margin: auto;
}

.blocCentre {
    position: relative;
    margin: auto;
    border: 4px solid lightgrey;
}

.floating-box {
    float: left;
    width: 150px;
    height: 75px;
    margin: 5px;  
}

.after-box {
    clear: left;      
}
   img {position: relative; top: 8px}