DDS format is a Microsoft format, sort of based on DXT format, which stands for Direct Draw Surface in case you were curious. It is geared towards compatibility with Microsoft's Direct X, which can use Mip Maps with the file. Mip Maps are proportionally smaller versions of the texture, which can be saved on a DDS file, which your graphics card can then use to display on your model at smaller sizes without the graphics card having to waste processing power on working out how to scale the texture down and re-interpolate the pixels. So mip mapping makes your textures look better at a distance and your computer draws them a bit quicker too since part of the scaling work is already done for it. If you turn on anisotropic filtering, it also means the texture is less likely to get moire patterns (i.e those weird interference patterns you occasionally see) when viewed at oblique angles.
with Paint.net you get built in support for DDS files, and so if you open up a texture and faff about with it, you might have to resave the mip maps too. How you do that is to choose 'save as' from the file menu, and if you choose DDS file format, you will see a little option box pop up that has 'other options' listed on it at the bottom, one of which is a tick box that says 'generate mip maps'. So if you tick that, you'll get a mip mapped file.
But if your texture did not have mip maps on it originally, then having mip maps on your repaint will feck it up, so you don't always need to generate them, and the simplest way to find that out is to either open the image up with the mip maps showing (this can lead to problems when saving though), or just try saving the file both ways and see which one works for your repaint. As with everything repaint-wise, making back up copies of things first is a wise precaution, just in case you are unsure about stuff.
Al
|