henkbein wrote:
1.Create the following subdirs in your Supreme Commander directory:
2. "env\Yourmapname\Decals"
2.1 "env\Yourmapname\Layers" (if you wish to make custom layers also)
3. Use image size 1024 x 1024
4. Save any decal images in the "env\Yourmapname\Decals" directory
4.1 Save any Stratum images in the "env\Yourmapname\Layers" directory
6. Save all images as .dds files, DXT5 (interpolated alfa).

If you don't have the image software for DXT5, simply download: Paint.net + dds plug in for Paint.net
Even if you don't like the user interface (i don't) you can simply copy/paste from your favorite image editor into this program and save the result.