@Renny, that is not included in this mod. You can edit the calender event templates and include the following rough example:
Code:
<if condition="$eventinfo['calendarid'] == 'CALENDAR_ID'"> IMAGE_CODE </if>
It is tough to know exactly how the user in your screenshots created theirs, maybe a different event manager or a calendar per instance. On my site, I have a WoW calendar and it shows a WoW icon next to events scheduled for it. The CALENDER_ID is the number for the calender, in my case "3" and the IMAGE_CODE is the WoW icon.
This is something you will have to work out on your own however, you will need to be comfortable with customizing various templates.
@Sedition-Guild, Kinneas is correct, thank you.