As the title says, I want to create DDS images with custom mipmaps only using Paint.net.
This could be done by using layers in a similar way to how animated images can be made.
For example, we have a 512x512 image, then we import an image half that size with whatever we want the next mipmap to be as a seperate layer.
Then we have a 256x256 texture in the top right corner of the image while still retaining the 512x512 canvas size.
If there's already a plugin that does this, then please tell me.