Convert sgi to dds Online: sgi2dds
You can use Tom's Editor to easily convert images from
Silicon Graphics RGB .SGI to Direct Show Surface
Tom's Editor is a free, online image manipulation and converter program.
Go to Tom's Editor
Silicon Graphics RGB is an image format with extension SGI.
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.