MyBB Community Forums

Basically, in ACP, I got to Forums and Posts, and click "Add New Forum"

I then add a child forum, but place it as a Category.

When I then look at my website as a whole, the image used for the thumbnail is off.png.

How can I edit my code so that categories take custom icons just like my forums do (uploading 68.png, 69.png etc. with the number as the forum's ID)?

You need the plugin called "Ficons" from mybbcentral.com. You have to subscribe to get it as it is a premium plugin.

http://community.mybb.com/thread-53881.html

You can use a tutorial like this (There are a few of them) to get it done.