Add image to the left of a label

I know how to add something like an asterisk next to a label, but I cannot figure out how to put an image to the left of a label. Can someone show me how? It is to show a required field.

Old Code putting an asterisk next to a label:

<!--Markup-->
<div class="row">
	<label class="required">Incident Type</label>
</div>
 
/*CSS*/
.required:after 
{
    color: red;
    content: ' *';
}

I need to know how to put an image before the label instead.

Thank you