Image MIME Reference
VTF
Valve Texture Format
image/vnd.valve.source.texture
VS
Windows Metafile
image/x-wmf
WMF
A complete technical comparison of Valve Texture Format and Windows Metafile — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | VTF | WMF |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
Valve Texture Format
image/vnd.valve.source.texture
Extension
.vtf
Container
Valve Texture Format Header
Compression
DXTC (DXT1, DXT3, DXT5) / Uncompressed (BGRA8888, RGB888, etc.)
Algorithm
DXT1-DXT5None
Color Depth
8-bit, 24-bit (RGB), 32-bit (RGBA), 16-bit Floating Point (HDR)
Developed by
Valve Corporation
Released
2004
Magic Bytes
56 54 46 00
Windows Metafile
image/x-wmf
Extension
.wmf.emf
Container
Windows GDI Metafile Command Stream
Compression
Uncompressed (Command Stream)
Algorithm
None
Color Depth
Varies based on GDI rendering engine
Developed by
Microsoft Corporation
Released
1990
Magic Bytes
D7 CD C6 9A (Aldus Placeable Metafile Header) or 01 00 09 00 (Standard WMF Header)
Browser Support Comparison
| Browser | VTF | WMF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ |
✓
|
VTF
VTF Strengths
- Extremely fast loading within the Source Engine because the block-compressed data goes directly into the GPU's VRAM without CPU decompression overhead
- Bundles mipmaps, volumetric slices, cubemap faces, and animation frames entirely within a single file
- Openly documented by the Valve Developer Community, leading to a massive ecosystem of third-party modding tools
Limitations
- Strictly tied to the Source Engine ecosystem; entirely useless in standard web or print contexts
- No native support in standard image editors without hunting down and installing specialized plugins
- Block compression algorithms (DXT) are lossy and can cause visible artifacting, especially on normal maps or smooth gradients
WMF
WMF Strengths
- Infinitely scalable vector format that remains remarkably compact for simple geometric illustrations and charts
- Historically served as a seamless conduit for copying and pasting vector graphics between disparate Windows applications via the system clipboard
Limitations
- Notoriously plagued by historic security vulnerabilities, making raw WMF parsing a vector for exploits in legacy software
- Completely obsolete and unsupported in modern web environments (browsers cannot render them)
- Strictly tied to the Windows GDI architecture, making cross-platform rendering inconsistent across Linux and macOS
When to choose which format
VTF
Use VTF when…
- Source Engine Game Textures
- Custom Maps and Modding (Garry's Mod, CS:GO)
- Animated In-Game Decals and Sprays
- Environment Cubemaps (Skyboxes)
WMF
Use WMF when…
- Legacy Microsoft Office Clip Art and Icons
- Windows GDI Graphics Export
- Early Windows Desktop Publishing