This dose not work, ue4 dosent import those files. More here: https://answers.unrealengine.com/questions/32577/view.html
As of exporting Gimp DDS plugin seams menagable. Also more resources:DDS texture tools - Nexus Mods Wiki
If you have any idea how to force unreal to import custom mipmaps for standard 2D texture please help.
Its like twelfth time I needed that and couldn’t do it and Im going quite mad.