Designer — jewlery

Hi, I have a dropdown menu in my main site navigation containing a list of collections, and I want to show the image for each of those collections next to the link in the nav. I managed to do the if statement to show an image, but it's not pulling in the collection image (just the Shopify standard 'no image' image. I am using the Vermont theme and can see that the code needs to go in the meganav.liquid snippet file. Could you please help by supplying the code I need to use and where I need to add it please?