Image MIME Reference
EMF
Windows Enhanced Metafile
image/x-emf
VS
Extended Image File Format
image/vnd.xiff
XIFF
A complete technical comparison of Windows Enhanced Metafile and Extended Image File Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | EMF | XIFF |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Windows Enhanced Metafile
image/x-emf
Extension
.emf
Container
Windows GDI/GDI+ Record Sequence
Compression
Uncompressed (Binary Drawing Records)
Algorithm
None
Color Depth
Vector (32-bit GDI/GDI+ Colors), Supports embedded 24-bit/32-bit bitmaps
Developed by
Microsoft Corporation
Released
1993
Magic Bytes
01 00 00 00 (Header Type) ... 20 45 4D 46 (Signature at offset 40)
Extended Image File Format
image/vnd.xiff
Extension
.xif
Container
TIFF-based Proprietary Container
Compression
CCITT Group 3 / Group 4 / LZW / Uncompressed
Algorithm
CCITT Group 4LZWNone
Color Depth
1-bit (Monochrome), 8-bit (Grayscale), 24-bit (RGB)
Developed by
Keyfile Corporation
Released
1994
Magic Bytes
49 49 2A 00 or 4D 4D 00 2A
Browser Support Comparison
| Browser | EMF | XIFF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✓
|
✕ |
EMF
EMF Strengths
- Device independent, meaning it renders consistently across different monitors and printers regardless of resolution
- Fully supports 32-bit precision and advanced GDI+ drawing commands, including alpha transparency and anti-aliasing (EMF+)
- Native rendering within the Windows OS ensures fast performance and flawless fidelity in Microsoft Office applications
Limitations
- Heavily tied to the Windows Graphics Device Interface API, making it notoriously difficult to parse perfectly on macOS or Linux
- Completely unsupported by modern web standards; cannot be embedded in HTML without conversion to SVG
- Security history: Like WMF, malicious drawing records can theoretically exploit vulnerabilities in older GDI parsers
XIFF
XIFF Strengths
- Pioneered early enterprise document workflow integration by binding administrative routing data directly to the document image file
- Leveraged efficient fax compression standards to keep storage requirements low on 1990s server infrastructure
Limitations
- Completely proprietary and obsolete; Keyfile Corporation's software ecosystem no longer exists
- Causes widespread MIME type identification conflicts due to sharing the exact same binary header signature as standard TIFF files
- Zero support in modern operating systems or web browsers
When to choose which format
EMF
Use EMF when…
- Microsoft Office Vector Graphics and Clip Art
- Windows Print Spooling (EMF Spool Files)
- High-fidelity Vector Interchange on Windows
XIFF
Use XIFF when…
- Keyfile Enterprise Document Management
- Legacy Corporate Workflow Archival
- Scanned Multi-page Document Routing