Importing textures with an alpha channel (BC3 and 8.8.8.8).

2 Narron
In Photoshop, you can safely save in PNG format without a background; the main thing is not to merge the layers beforehand.
If I understand correctly.

That's correct, DDS doesn't handle that well. Since I don't use Photoshop plugins, I open PNG files in Paint.net and use the magic wand tool to remove any remaining empty areas. Then, to check for the absence of a white background, I select the DDS save option with B8G8R8XB settings (Linear X8R8G8B8). On a small screen, when this setting is selected, a white or black color is displayed. If there is no white color where the empty areas were, it means everything is fine, and I choose the other settings I need for the DDS file.