VTFEdit

VTFEdit is a .NET-based graphical frontend tool for creating, viewing, and converting Valve Texture Format (VTF) and Valve Material Type (VMT) files. It supports multiple image formats including BMP, DDS, GIF, JPG, PNG, and TGA, and offers features such as mipmap generation, DXT compression, normal map creation, and batch conversion. Developed by Ryan Gregg and Neil Jedrzejewski, it is widely used for texture editing in Source engine games.