From Halopedia, the Halo wiki

The wiki contains hundreds of images and music files that we do our best to keep track of. From small to large files, every image we Halopedians upload requires a license template. It ensures the copyrights from Microsoft and organizes the files into the correct categories in our database.

When attempting to upload a file to this very wiki, there is a box on the page that manages the license template. When the file is uploaded, it is automatically put into the proper category. Take your best guess, but if you have no idea of what kind of license would be suitable for your file, choose the last option in the drop-down menu.