Hi Gregory,
I am great and I hope you will be doing good.
We can display the icon in quick popup using template and for the sample prepared the below sample.
<script id="footerTemplate" type="text/x-template">
<div>
${if (elementType === 'cell')}
<div class="e-cell-footer">
<button class="e-event-details" title="Additional Details">Additional Details</button>
<img src="https://ej2.syncfusion.com/javascript/demos/src/schedule/images/environment-day.svg" alt="flower" />
<button class="e-event-create" title="Add">Add</button>
</div>
${else}
<div class="e-event-footer">
<button class="e-event-edit" title="Edit">Edit</button>
<img src="https://ej2.syncfusion.com/javascript/demos/src/schedule/images/environment-day.svg" alt="flower" />
<button class="e-event-delete" title="Delete">Delete</button>
</div>
${/if}
</div>
</script>
Regards,
Karthigeyan