When you create your Config, you have to enter a Codename. This is the name of the folder your Config is created as.

From now on whenever I write [Codename], it means whatever you chose for the Config.

Find your Local Config in data/nzombies-unlimited/localconfigs/[Codename].

• If you just want the Thumbnail on the Local Config

Save your thumbnail as [Codename].jpg and put it inside your config's folder.

• If you want your Config on the Workshop with the thumbnail

Follow the steps of the Sharing guide and place save the image to materials/nzombies-unlimited/configthumbnails/[Codename].jpg inside your Addon folder.