DXT is a texture compression format, formerly known as S3TC. dxt) file format and type. While we do not yet have a description of the DXT file format and what it is normally used for, we do know which programs are known to open these files. DXT file: Microsoft DirectX Compressed Texture Data. Crystal Logics crossed the limits of our software working from Image TXT format to DXT format. There are five variations of the S3TC algorithm (named DXT1 through DXT5, referring to the FourCC code assigned by Microsoft to each format), each designed.