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Image MIME Reference
SGI

Silicon Graphics Image

image/sgi
VS

Truevision TGA (Legacy MIME Alias)

image/x-tga
TGA

A complete technical comparison of Silicon Graphics Image and Truevision TGA (Legacy MIME Alias) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature SGI TGA
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 →
Truevision TGA (Legacy MIME Alias)
image/x-tga
Extension
.tga.icb.vda.vst
Container Truevision TGA Footer/Header
Compression Uncompressed / Run-Length Encoding (RLE)
Algorithm
NoneRLE
Color Depth 8-bit (Grayscale or Indexed), 16-bit (High Color), 24-bit (True Color), 32-bit (True Color with Alpha Channel)
Developed by Truevision Inc.
Released 1984
Magic Bytes
54 52 55 45 56 49 53 49 4F 4E 2D 58 46 49 4C 45 2E 00 (At the end of the file)
Full TGA reference →

Browser Support Comparison

Browser SGI TGA
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
TGA

TGA Strengths

  • Incredibly simple byte layout allows developers to write custom loaders and exporters in a few dozen lines of code, bypassing the need for heavy external libraries
  • Native support for 8-bit alpha channels ensures flawless transparency masking for real-time 3D rendering
  • Fast, predictable RLE decoding requires almost no CPU overhead compared to DEFLATE (PNG) or DCT (JPEG)
Limitations
  • RLE compression is relatively weak by modern standards, resulting in large file sizes
  • Lacks a standard magic byte header at the beginning of the file, making file-sniffing unreliable for older v1.0 files
  • Zero support in web browsers; must be converted to PNG or WebP for web delivery

When to choose which format

SGI
Use SGI when…
  • Legacy 3D Animation & VFX
  • Silicon Graphics IRIX Workflows
  • Historical CGI Archiving
TGA
Use TGA when…
  • Video Game 3D Textures and Materials
  • 3D Rendering and Animation Sequences
  • Legacy Video Production Workflows

More comparisons

SGI vs ACES → TGA vs ACES → SGI vs APNG → TGA vs APNG → SGI vs AVCI → TGA vs AVCI → SGI vs AVCS → TGA vs AVCS → SGI vs AVIF → TGA vs AVIF → All comparisons →
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