The .tex files in TQ are a container format for (mostly) malformed .dds files, so here are some tools to extract, fix and compile them.
Download: TQ Texture Tools
The zip file contains two small programs to extract and compile .tex files. Just drag a .tex file or a folder on TQ.Texture.Extract to extract all dds data from that file/folder.
To compile a .dds to .tex, drag it onto TQ.Texture.Compile. Read the readme for more information on cubemaps and animations.
Using these tools, you can create lossless skins if you have a program that can natively edit DXT compressed data (Photoshop with .dds plug-in).
Programmers can use the TQ.Texture.dll to load .tex files directly into their programs. PM me for more info!