Template talk:WikiCicada

Image
I'm not too great with WikiCode, so how can I make it so that the image is the Brown Cicada if nothing is put into the parameter, then if the user puts something into the parameter then the image switches to the chosen cicada type? I took a look at Template:UB Fav Bug for reference but that didn't seem to help all that much. 12:40, September 23, 2020 (EDT)