<div class="row">
    <div class="col-xs-6 col-md-3">
        <a href="#" class="thumbnail">
            <img data-src="holder.js/100%x180" alt="100%x180"
                 src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIxNzEiIGhlaWdodD0iMTgwIj48cmVjdCB3aWR0aD0iMTcxIiBoZWlnaHQ9IjE4MCIgZmlsbD0iI2VlZSI+PC9yZWN0Pjx0ZXh0IHRleHQtYW5jaG9yPSJtaWRkbGUiIHg9Ijg1LjUiIHk9IjkwIiBzdHlsZT0iZmlsbDojYWFhO2ZvbnQtd2VpZ2h0OmJvbGQ7Zm9udC1zaXplOjEycHg7Zm9udC1mYW1pbHk6QXJpYWwsSGVsdmV0aWNhLHNhbnMtc2VyaWY7ZG9taW5hbnQtYmFzZWxpbmU6Y2VudHJhbCI+MTcxeDE4MDwvdGV4dD48L3N2Zz4="
                 style="height: 180px; width: 100%; display: block;">
        </a>
    </div>
    <div class="col-xs-6 col-md-3">
        <a href="#" class="thumbnail">
            <img data-src="holder.js/100%x180" alt="100%x180"
                 src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIxNzEiIGhlaWdodD0iMTgwIj48cmVjdCB3aWR0aD0iMTcxIiBoZWlnaHQ9IjE4MCIgZmlsbD0iI2VlZSI+PC9yZWN0Pjx0ZXh0IHRleHQtYW5jaG9yPSJtaWRkbGUiIHg9Ijg1LjUiIHk9IjkwIiBzdHlsZT0iZmlsbDojYWFhO2ZvbnQtd2VpZ2h0OmJvbGQ7Zm9udC1zaXplOjEycHg7Zm9udC1mYW1pbHk6QXJpYWwsSGVsdmV0aWNhLHNhbnMtc2VyaWY7ZG9taW5hbnQtYmFzZWxpbmU6Y2VudHJhbCI+MTcxeDE4MDwvdGV4dD48L3N2Zz4="
                 style="height: 180px; width: 100%; display: block;">
        </a>
    </div>
    <div class="col-xs-6 col-md-3">
        <a href="#" class="thumbnail">
            <img data-src="holder.js/100%x180" alt="100%x180"
                 src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIxNzEiIGhlaWdodD0iMTgwIj48cmVjdCB3aWR0aD0iMTcxIiBoZWlnaHQ9IjE4MCIgZmlsbD0iI2VlZSI+PC9yZWN0Pjx0ZXh0IHRleHQtYW5jaG9yPSJtaWRkbGUiIHg9Ijg1LjUiIHk9IjkwIiBzdHlsZT0iZmlsbDojYWFhO2ZvbnQtd2VpZ2h0OmJvbGQ7Zm9udC1zaXplOjEycHg7Zm9udC1mYW1pbHk6QXJpYWwsSGVsdmV0aWNhLHNhbnMtc2VyaWY7ZG9taW5hbnQtYmFzZWxpbmU6Y2VudHJhbCI+MTcxeDE4MDwvdGV4dD48L3N2Zz4="
                 style="height: 180px; width: 100%; display: block;">
        </a>
    </div>
    <div class="col-xs-6 col-md-3">
        <a href="#" class="thumbnail">
            <img data-src="holder.js/100%x180" alt="100%x180"
                 src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIxNzEiIGhlaWdodD0iMTgwIj48cmVjdCB3aWR0aD0iMTcxIiBoZWlnaHQ9IjE4MCIgZmlsbD0iI2VlZSI+PC9yZWN0Pjx0ZXh0IHRleHQtYW5jaG9yPSJtaWRkbGUiIHg9Ijg1LjUiIHk9IjkwIiBzdHlsZT0iZmlsbDojYWFhO2ZvbnQtd2VpZ2h0OmJvbGQ7Zm9udC1zaXplOjEycHg7Zm9udC1mYW1pbHk6QXJpYWwsSGVsdmV0aWNhLHNhbnMtc2VyaWY7ZG9taW5hbnQtYmFzZWxpbmU6Y2VudHJhbCI+MTcxeDE4MDwvdGV4dD48L3N2Zz4="
                 style="height: 180px; width: 100%; display: block;">
        </a>
    </div>
</div>