Create Your Own Icons for the Gantt
Where: This change applies to Lightning Experience and Salesforce Classic in Enterprise, Performance, Unlimited, and Developer editions with the Field Service Lightning managed package installed.
How: After you add the Gantt Icon field to service appointment page layouts, you can enter an icon URL in the field for any service appointment. The URL must end in an image suffix, such as .png or .gif. Images with a transparent background appear with a white background on the Gantt.
For example, add an ice cream icon to an appointment that’s next to your favorite ice cream shop. Find a URL that leads to an ice cream icon, and paste the link in the appointment’s Gantt icon field. (Of course, we recommend scheduling a snack break after the appointment.)