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Image MIME Reference
SGI

Silicon Graphics Image

image/sgi
VS

Windows Metafile

image/x-wmf
WMF

A complete technical comparison of Silicon Graphics Image and Windows Metafile — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature SGI WMF
Transparency (Alpha) Yes Yes
Animation Support ✕ No ✕ No
Progressive Loading ✕ No ✕ No
HDR Support ✕ No ✕ No
EXIF Metadata ✕ No ✕ No
ICC Color Profile ✕ No ✕ No
Silicon Graphics Image
image/sgi
Extension
.sgi.rgb.rgba.bw.int.inta
Container SGI Image Format
Compression Uncompressed / Lossless (Run-Length Encoding)
Algorithm
RLENone
Color Depth 8-bit, 16-bit (Per Channel)
Developed by Paul Haeberli (Silicon Graphics)
Released 1990
Magic Bytes
01 DA
Full SGI reference →
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)
Full WMF reference →

Browser Support Comparison

Browser SGI WMF
Chrome Chrome
Firefox Firefox
Safari Safari
Edge Edge
IE IE (Legacy)
SGI

SGI Strengths

  • Pioneered multi-channel and 16-bit per channel imaging capabilities required for high-end 1990s visual effects
  • Extremely robust and simple header structure
  • Reliable Run-Length Encoding provided solid lossless compression for flat-shaded 3D renders
Limitations
  • Completely obsolete for modern web and application development
  • Zero native web browser compatibility
  • Largely replaced by TIFF and OpenEXR in modern professional VFX and 3D pipelines
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

SGI
Use SGI when…
  • Legacy 3D Animation & VFX
  • Silicon Graphics IRIX Workflows
  • Historical CGI Archiving
WMF
Use WMF when…
  • Legacy Microsoft Office Clip Art and Icons
  • Windows GDI Graphics Export
  • Early Windows Desktop Publishing
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