Malcolm,
get DXTBmp by Martin Wright. Go here:
http://www.btinternet.com/~mnwright/ and click on the sixth icon in the second row to get to the DXTBmp. Download is at the bottom of the page.
When you start the program, load your texture and then put in the tick mark to the right of the screen under "MipMaps" "Include when saving". That's it.
Alternatively, you could use Imagetool which comes with terrain SDK for Flight simulator 2004. In Imagetools go under "Image" and "Create MipMaps"
http://download.microsoft.com/download/4/f...n_sdk_setup.exeRegards,
Jure