Free webp to jpg
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Image MIME Reference
Harlequin-PGB

Global Graphics Page Graphics Buffer

image/vnd.globalgraphics.pgb
VS

JPEG 2000 Compound Image File Format

image/jpm
JPM

A complete technical comparison of Global Graphics Page Graphics Buffer and JPEG 2000 Compound Image File Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature Harlequin-PGB JPM
Transparency (Alpha) ✕ No Yes
Animation Support ✕ No ✕ No
Progressive Loading ✕ No Yes
HDR Support ✕ No ✕ No
EXIF Metadata ✕ No Yes
ICC Color Profile Yes Yes
Global Graphics Page Graphics Buffer
image/vnd.globalgraphics.pgb
Extension
.pgb
Container Proprietary Harlequin Raster Container
Compression Uncompressed / Run-Length Encoding (RLE)
Algorithm
Proprietary RLENone
Color Depth 1-bit (Monochrome Separations), 8-bit (Grayscale), 8-bit/10-bit (Contone), CMYK / N-Color Spot Channels
Developed by Global Graphics Software (Hybrid Software Group)
Released 1990s
Magic Bytes
Unknown (Proprietary Harlequin Header)
Full Harlequin-PGB reference →
JPEG 2000 Compound Image File Format
image/jpm
Extension
.jpm.jpgm
Container ISOBMFF / JPM (ISO/IEC 15444-6)
Compression Lossy / Lossless / Mixed Raster Content (MRC)
Algorithm
JPEG 2000JBIG2JPEGMMR
Color Depth 1-bit (Text/Masks), 8-bit, 16-bit, 24-bit
Developed by Joint Photographic Experts Group (JPEG)
Released 2003
Magic Bytes
00 00 00 0C 6A 50 20 20 0D 0A 87 0A ... 66 74 79 70 6A 70 6D 20
Full JPM reference →

Browser Support Comparison

Browser Harlequin-PGB JPM
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
Harlequin-PGB

Harlequin-PGB Strengths

  • Unlike generic 1-bit TIFFs, PGB files inherently encapsulate vital print-job metadata within their headers (e.g., job name, page number, separation colors, screening angles)
  • Highly optimized for ultra-fast viewing and processing within professional printing workflows
Limitations
  • Completely proprietary and closed-source, locking its usage strictly to Harlequin-powered RIP environments
  • Zero support in standard desktop operating systems, web browsers, or consumer image editing software like Photoshop or GIMP
JPM

JPM Strengths

  • Highly optimized for scanned documents, drastically reducing file sizes without sacrificing the readability of text or the quality of embedded photos
  • Supports multi-page documents within a single file
  • Object-based architecture allows for complex layout representation and independent extraction of elements
Limitations
  • Failed to achieve widespread adoption, largely being overshadowed by PDF/A and DjVu
  • Zero native web browser compatibility
  • Requires complex, specialized software to properly encode and decode the multi-layered MRC structure

When to choose which format

Harlequin-PGB
Use Harlequin-PGB when…
  • Commercial Printing Output
  • Computer-to-Plate (CTP) Manufacturing
  • Prepress Soft Proofing (e.g., FirstPROOF)
  • Harlequin RIP Spooling Pipelines
JPM
Use JPM when…
  • Scanned Document Archiving
  • Mixed Raster Content (MRC) Imaging
  • Digital Libraries

More comparisons

Harlequin-PGB vs ACES → JPM vs ACES → Harlequin-PGB vs APNG → JPM vs APNG → Harlequin-PGB vs AVCI → JPM vs AVCI → Harlequin-PGB vs AVCS → JPM vs AVCS → Harlequin-PGB vs AVIF → JPM vs AVIF → All comparisons →
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