<div class="jumbotron">
        <div class"textholder">

            <h1>this is a test</h1>

            <h3>this is a test</h3>

        </div>

        <div class="holder">
            <img src="Devicesmodded.png" style="max-width:100%;height:auto;">
        </div>
</div>

.textholder {

    margin:0 auto;
    width: 15%;

}