Image MIME Reference
DjVu
DjVu Document
image/vnd.djvu
VS
Silicon Graphics Image
image/x-rgb
SGI-RGB
A complete technical comparison of DjVu Document and Silicon Graphics Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | DjVu | SGI-RGB |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
DjVu Document
image/vnd.djvu
Extension
.djvu.djv
Container
Interchange File Format (IFF)
Compression
JB2 (Bi-tonal Text) / IW44 (Wavelet Background) / BZZ (General Data/Text)
Algorithm
JB2IW44BZZ
Color Depth
1-bit (Foreground Text), 24-bit (Background)
Developed by
AT&T Labs (Yann LeCun, Léon Bottou, Patrick Haffner, Paul G. Howard)
Released
1996
Magic Bytes
41 54 26 54 46 4F 52 4D
Silicon Graphics Image
image/x-rgb
Extension
.rgb.sgi.rgba.bw.int.inta
Container
SGI Image Header (512 bytes)
Compression
Uncompressed / Run-Length Encoding (RLE)
Algorithm
NoneScanline RLE
Color Depth
8-bit (Per Channel), 16-bit (Per Channel)
Developed by
Silicon Graphics, Inc. (Paul Haeberli)
Released
1988
Magic Bytes
01 DA
Browser Support Comparison
| Browser | DjVu | SGI-RGB |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
DjVu
DjVu Strengths
- Unmatched compression ratios for high-resolution scanned documents (often 5 to 10 times smaller than equivalent JPEG/TIFF-based PDFs)
- Separates text layers cleanly from backgrounds, allowing for highly legible text even at low file sizes
- Embedded OCR (Optical Character Recognition) text layers allow for fast searching
Limitations
- Lacks native support in modern operating systems and web browsers, requiring third-party software
- Largely superseded by PDF/A and modern PDF compression standards in standard corporate workflows
- Not suitable for vector graphics or born-digital documents (like Word exports), where standard PDF is far superior
SGI-RGB
SGI-RGB Strengths
- Supports 16-bit precision per channel and an embedded alpha channel, making it ideal for the demanding compositing workflows of 1990s cinema VFX
- The scanline-based RLE compression was exceptionally fast to decode on classic MIPS-based SGI workstations
- Features a straightforward 512-byte header, making it relatively easy to parse and write custom decoders in C or Python
Limitations
- Completely obsolete and unsupported in modern web environments
- Replaced entirely by TIFF, OpenEXR, and PNG in modern visual effects and 3D rendering pipelines
- Lacks support for modern color management via ICC profiles or advanced EXIF metadata
When to choose which format
DjVu
Use DjVu when…
- Scanned Books and Manuals
- Digital Libraries (e.g., Internet Archive)
- Historical Document Archiving
SGI-RGB
Use SGI-RGB when…
- Legacy 3D Animation and VFX Textures
- Silicon Graphics IRIX Workstation Archival
- 1990s Medical Imaging