What is a DDS file?
DDS, DirectDraw Surface, is Microsoft's container for textures that go straight to the graphics card. Instead of ordinary pixels it usually holds block-compressed data in formats like DXT1, DXT5, BC5, or BC7, which the GPU can read without decompressing, together with a chain of progressively smaller mipmaps used when the texture is seen from far away. That is why nearly every PC game and engine, from Skyrim and Fallout to Unity and Unreal, stores its textures as DDS.
How to open a DDS file
Ordinary image viewers cannot decode the GPU compression. Windows Photos, Paint, and browsers show nothing; Photoshop and GIMP need a plugin; Paint.NET has built-in support. The quickest route is to convert the DDS to PNG here: the converter decodes DXT1 through BC7 and uncompressed layouts in your browser and gives you a lossless PNG with the alpha channel intact.
Making DDS textures for a game
To go the other way, convert your PNG or TGA to DDS with DXT1 for opaque textures, DXT5 for textures with transparency, and generate mipmaps unless the texture is a UI element shown at a fixed size. Many engines require power-of-two dimensions such as 512, 1024, or 2048, so resize first if needed. Normal maps, specular maps, and other data textures follow game-specific rules; check the mod community for the title you are working on.
Frequently asked questions
What is the difference between DXT1 and DXT5?
DXT1 stores no usable alpha channel and is half the size; DXT5 keeps smooth transparency. Both compress colors the same way.
Why do the colors of a DDS look wrong?
Many game textures are not pictures: normal maps look blue or red-green, and specular or roughness data may live in the alpha channel. The file is decoded correctly; it just was not meant to be viewed.
Can DDS be converted without losing quality?
Decoding to PNG is lossless. Encoding to DXT is lossy, like JPG, though at texture sizes it is rarely visible in-game.