How do I generate the correct URL to my controller that renders an image on the fly?

this is my image element:

<img src="@dnnUrlHelper.Action("EventImageFromDB", "Calendar", new { eventID= item.EventID })" alt="Event" class="event-image" style="width:100%">

this works fine until the module is placed somewhere other than the Home page. The Action method is returning the incorrect URL path