I just used a canvas with a 1:2 ratio, that’s how you get it to be long enough to stretch across the whole thing. Then in the folder description, I uploaded said image just using the little image icon in the text editor thingy. After you put the image in, click on it and there’ll be a menu at the bottom where you can add a link. Just put the link of the folder you want it to open. So my “primary“ folder, the one with crystal on it, is linked to that folder (https://toyhou.se/cryx/characters/folder:3579079) 

also, don’t put any characters in that folder! Make sub folders and put them there :D