Center an image on a button

Hi Guys,
this may sound easy, but i have not found any way to center my stop sign in the below code,
I tried playing with paddings, with css margin-left: & margin-right:, with text-align:center and a few more. But it’s not working as expected.

Do you have any further idea?
2018-01-10_10-21-01

<!-- Button Manual https://www.w3schools.com/bootstrap/bootstrap_buttons.asp 
https://www.w3schools.com/css/css3_buttons.asp
-->

<style>
  .blinds_UP_DOWN_control-table {
	width: 100%;
	height: 100%;
	text-align: right;
	top:0px;
	bottom:0px;
	left:0px;
	right:0px;
	position:absolute
  }

  .blinds_UP_DOWN_control {
    position: relative;
    background-color: #CCCCCC;
    border: 1;
    font-size: 20px;
    color: #000000;
    text-align: center;
    -webkit-transition-duration: 0.4s; /* Safari */
    transition-duration: 0.4s;
    text-decoration: none;
    overflow: hidden;
    cursor: pointer;
}

.blinds_UP_DOWN_control:after {
    content: "";
    background: #f1f1f1;
    display: block;
    position: absolute;
    padding-top: 300%;
    padding-left: 350%;
    margin-left: -20px !important;
    margin-top: -120%;
    opacity: 0;
    transition: all 0.8s
}

.blinds_UP_DOWN_control:active:after {
    padding: 0;
    margin: 0;
    opacity: 1;
    transition: 0s
}
</style>

<table class="blinds_UP_DOWN_control-table" border="0">
	<tr>
			<td  style="width: 33%;height: 100%">
				<button class="blinds_UP_DOWN_control" style="width: 100%;height: 100%" ng-click="sendCmd(config.blinds_level, 'UP') ">▲</button>
      </td>
			<td style="width: 33%;height: 100%">
        <button class="blinds_UP_DOWN_control" style="width: 100%;height: 100%" ng-click="sendCmd(config.blinds_level, 'STOP') "><img src="/static/icon-stop.svg" width="100%"></img><br>{{itemValue(config.blinds_level)}}</br></button> 
      </td>
			<td  style="width: 33%;height: 100%">
        <button class="blinds_UP_DOWN_control" style="width: 100%;height: 100%" ng-click="sendCmd(config.blinds_level, 'DOWN') ">▼</button>
      </td>
  </tr>
</table> 

Thank you Andreas

The code was and is absolute correct to center that image, BUT if the Image is not perfect square it won’t work :slight_smile:
So, after adjusting the right part of the icon and removing the transparent stuff i don’t need this image is perfect centered.

BR
Andreas