Convert duo to dds Online: duo2dds

You can use Tom's Editor to easily convert images from
DU1, DUO .DUO to Direct Show Surface .DDS.
Tom's Editor is a free, online image manipulation and converter program.

Go to Tom's Editor

DUO

DU1, DUO is an image format with extension DUO.

DDS

DDS are files invented by Microsoft to be used in games, mostly as textures. Images can be compressed to save space but the compression methods defined by DDS are all very fast in terms of coding and decoding.