Example
<select class="form-control" multiple data-onload-select2='{"minimumResultsForSearch": "Infinity"}'>
<option
selected
data-image-src="//satyr.io/40x40/forestgreen"
data-image-width="40"
data-image-height="40"
>Forest green</option>
<option
selected
data-image-src="//satyr.io/40x40/crimson"
data-image-width="40"
data-image-height="40"
>Crimson</option>
<option
data-image-src="//satyr.io/40x40/steelblue"
data-image-width="40"
data-image-height="40"
>Steel blue</option>
</select>