From WoWWiki

RE: WC3 icons

Firstly, the reason they were placed into Category:Warcraft III map editor images cause they page they were on was labeled "WC3 Icons/Map editor icon library", one would assume they were going to be from warcraft 3's map editor.

Second, yes WoW icons wouldn't be easily quick searchable if only placed in Category:Wow User Interface images, thats why they have many subcategories within subcategories within a category. The reason WoW Icons: <category name> was used over World of Warcraft Icons: <category name> is that the name of the category would get ridiculously long. Whereas Warcraft III is not long and is the preferred way.

Category:Warcraft III map editor images is a subcategory of Category:Warcraft III, if you wish to add subcategories to Category:Warcraft III map editor images please do so. You can use categories such as Category:Warcraft III Icons: <category name>. Sssssssssssssssssssssssss For Pony! ^{{TDon't hiss at me.•CIf you do things right, people won't be sure you've done anything at all.)} 23:02, 11 January 2009 (UTC)

That would be fine. Sssssssssssssssssssssssss For Pony! ^{{TDon't hiss at me.•CIf you do things right, people won't be sure you've done anything at all.)} 07:56, 12 January 2009 (UTC)