github Kraigose / KraigoseTools
Kraigose's eDuke32 Suite of Tools 
https://github.com/Kraigose/KraigoseTools

Waffle Iron Interactive
http://www.kraiggowaffles.com/programming/eduke32-art-tools/
www.kraiggowaffles.com/media/programs/eduke32/art_tile_tools_v002.zip