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Image MIME Reference
PTI

PTI Image (Personal/Vanity Tree)

image/prs.pti
VS

Silicon Graphics Image

image/sgi
SGI

A complete technical comparison of PTI Image (Personal/Vanity Tree) and Silicon Graphics Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature PTI SGI
Transparency (Alpha) ✕ No Yes
Animation Support ✕ No ✕ No
Progressive Loading ✕ No ✕ No
HDR Support ✕ No ✕ No
EXIF Metadata ✕ No ✕ No
ICC Color Profile ✕ No ✕ No
PTI Image (Personal/Vanity Tree)
image/prs.pti
Extension
.pti
Container Proprietary
Compression Unknown / Proprietary
Algorithm
Unknown
Color Depth Unknown
Developed by Jürn Laun
Released 1999
Magic Bytes
Unknown
Full PTI reference →
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 →

Browser Support Comparison

Browser PTI SGI
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
PTI

PTI Strengths

  • Provided a registered MIME type namespace for a specific application's proprietary image format without conflicting with standard web types
Limitations
  • Completely undocumented and unsupported in modern ecosystems
  • Zero web browser compatibility
  • Falls into the 'vanity' tree, making it irrelevant for standard cross-platform data exchange
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

When to choose which format

PTI
Use PTI when…
  • Legacy Application Specific Workflows
  • Proprietary Image Storage
SGI
Use SGI when…
  • Legacy 3D Animation & VFX
  • Silicon Graphics IRIX Workflows
  • Historical CGI Archiving

More comparisons

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