bs隙間系3

index.html

<div class="container" style="background-color: red; padding: 10px;"> <!-- padding:10px指定 -->
    <div class="row" style="background-color: green; margin-left: 0; margin-right: 0;"> <!-- .rowのネガティブマージンを削除 -->
        <div class="col-sm-4" style="background-color: blue;">
            <img src="./images/img1.jpg">
        </div>
        <div class="col-sm-4" style="background-color: yellow;">
            <img src="./images/img4.jpg">
        </div>
        <div class="col-sm-4" style="background-color: purple;">
            <img src="./images/img5.jpg">
        </div>
    </div>
</div>