Convert ngg to dds Online: ngg2dds

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

Go to Tom's Editor

NGG

Nokia Group Graphics is an image format with extension NGG.

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.