Free webp to jpg
Image MIME Reference
FreeHand

Macromedia FreeHand Document

image/x-freehand
VS

Portable Graymap

image/x-portable-graymap
PGM

A complete technical comparison of Macromedia FreeHand Document and Portable Graymap — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature FreeHand PGM
Transparency (Alpha) Yes ✕ No
Animation Support Yes ✕ No
Progressive Loading ✕ No ✕ No
HDR Support ✕ No Yes
EXIF Metadata ✕ No ✕ No
ICC Color Profile Yes ✕ No
Macromedia FreeHand Document
image/x-freehand
Extension
.fh.fh4.fh5.fh7.fh8.fh9.fh10.fh11.ft11
Container Proprietary Binary (Aldus Graphic Document)
Compression Uncompressed / Deflate (in later versions)
Algorithm
NoneDeflate (Optional in later versions)
Color Depth Vector Data (RGB/CMYK)
Developed by Altsys / Aldus / Macromedia
Released 1988
Magic Bytes
41 47 44 31 to 41 47 44 34
Full FreeHand reference →
Portable Graymap
image/x-portable-graymap
Extension
.pgm
Container Netpbm
Compression Uncompressed
Algorithm
None
Color Depth 8-bit (Grayscale), 16-bit (Grayscale)
Developed by Jef Poskanzer (Netpbm Project)
Released 1988
Magic Bytes
50 32 (ASCII) or 50 35 (Binary)
Full PGM reference →

Browser Support Comparison

Browser FreeHand PGM
Chrome Chrome
Firefox Firefox
Safari Safari
Edge Edge
IE IE (Legacy)
FreeHand

FreeHand Strengths

  • Historically one of the most powerful and intuitive vector editors on the market, praised for multi-page support long before Adobe Illustrator implemented it
  • Files are generally compact and self-contained
Limitations
  • Completely abandoned proprietary format; Adobe actively blocked native import in modern versions of Illustrator
  • No support in modern web browsers; must be converted to SVG
  • Versioning fragmentation means parsers must account for wildly different binary structures depending on the specific .fhX extension used
PGM

PGM Strengths

  • Extremely simple format allows custom parsers to be written from scratch in minimal time
  • Supports 16-bit precision, making it highly valuable for scientific, medical, and height-map data where 8-bit precision is insufficient
  • ASCII encoding ('P2') allows manual editing and visual inspection of pixel values directly within a text editor
Limitations
  • Strictly limited to grayscale; cannot display color
  • Lack of compression results in massive file sizes, making it entirely impractical for web delivery or consumer storage
  • Does not support alpha transparency or modern metadata structures

When to choose which format

FreeHand
Use FreeHand when…
  • Legacy Graphic Design Portfolios
  • Historical Desktop Publishing Archival
  • Old Corporate Logo Vectors
PGM
Use PGM when…
  • Computer Vision and Machine Learning Pre-processing
  • Scientific and Medical Image Processing
  • Unix/Linux Command-Line Image Pipelines
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