.alert-img-loading 
{
    background-image:url("/assets/img/loading.gif");
    background-repeat:  no-repeat;
    background-position: left 1rem center;
    padding-left: 3rem;
}

.alert-img-alert 
{
    background-image:url("/assets/img/alert.png");
    background-size: 24px;
    background-repeat:  no-repeat;
    background-position: left 1rem center;
    padding-left: 3rem;
}