Convert him to dds Online: him2dds

You can use Tom's Editor to easily convert images from
Hires Manager by Cosmos .HIM to Direct Show Surface .DDS.
Tom's Editor is a free, online image manipulation and converter program.

Go to Tom's Editor

HIM

Hires Manager by Cosmos is an image format with extension HIM.

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.