Convert png to dds Online: png2dds

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

Go to Tom's Editor

PNG

Portable Network Graphics is an image format with extension PNG.

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.