Thanks, but that won’t really do what I need. It would mean putting a link to the image for each individual event.
The people who put the events online on this website don’t really know that much about code (can’t say I know much about php), so my hope was that the #_EVENTIMAGE{x,y} placeholder could link to the event in the same way as #_LINKEDNAME does. So then someone could just set a featured image when creating the event and the image would appear as a link in the widget (or in a list of events, perhaps) and, when clicked on, the full event would appear with the featured image displayed again.
I guess what I’m asking for is a placeholder called #_EVENTIMAGELINKED{x,y} or something like that. Any ideas?