Let's go...
1.I create some tiles art file,for example,021.
2.I create some high texture,named 5439.png and create Sanek Folder
3.I create Sanek.def and write in duke3d.def:include include highres/Sanek.def
4.I write in Sanek.def:definetexture 5439 0 0 0 -1 -1 highres/Sanek/5439.png
5.Drag Sanek folder in Duke3d/Auotoload/duke3d.grp/duke3d_hrp/highres/