Convert psd to dds Online: psd2dds

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

Go to Tom's Editor

PSD

PSD is in internal image format of Adobe Photoshop. It can store all the features offered by Photoshop, like layers and paths. Images can be compressed or not.

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.