JSFiddle - React, Tailwind, and code Playground

HTML

<div id="ButtonBarDivUnit" class="ButtonBarDiv">
  <div id="imagecontainer">  
  <input type="image" src="http://upload.wikimedia.org/wikipedia/commons/2/2c/Opml-icon.svg"/>
    <input type="image" src="http://upload.wikimedia.org/wikipedia/commons/2/2c/Opml-icon.svg"/>
  </div></div>

CSS

#ButtonBarDivUnit {
  top:160px;
}
.ButtonBarDiv {
  background-color:yellow;
  width:280px;
  position:fixed;
  left:0px;
  border:1px solid blue;
  display:table;
  height:300px;
}
.ButtonBarDiv #imagecontainer {
display:table-cell;
text-align:center;
vertical-align:middle;
  width:100%;
}

.ButtonBarDiv input[type=image] {
  height: 24px;
}