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Image MIME Reference
PGM

Portable Graymap

image/x-portable-graymap
VS

Tagged Image File Format (Legacy MIME)

image/x-tiff
TIFF

A complete technical comparison of Portable Graymap and Tagged Image File Format (Legacy MIME) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature PGM TIFF
Transparency (Alpha) ✕ No Yes
Animation Support ✕ No ✕ No
Progressive Loading ✕ No ✕ No
HDR Support Yes Yes
EXIF Metadata ✕ No Yes
ICC Color Profile ✕ No Yes
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 →
Tagged Image File Format (Legacy MIME)
image/x-tiff
Extension
.tiff.tif
Container IFD (Image File Directory) Tag Structure
Compression Uncompressed / LZW (Lossless) / ZIP / Deflate (Lossless) / PackBits (Lossless RLE) / JPEG (Lossy) / CCITT Group 3/4 (Fax/Document)
Algorithm
NoneLZWDeflatePackBitsJPEGCCITT
Color Depth 1-bit (Monochrome), 8-bit (Grayscale or Indexed), 16-bit (Per Channel), 32-bit (Float Per Channel)
Developed by Aldus Corporation (Later acquired by Adobe Systems)
Released 1986
Magic Bytes
49 49 2A 00 (Little-endian) or 4D 4D 00 2A (Big-endian)
Full TIFF reference →

Browser Support Comparison

Browser PGM TIFF
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
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
TIFF

TIFF Strengths

  • Universally accepted as the gold standard for high-fidelity archival and professional print workflows
  • Highly adaptable structure supports multiple pages (documents), layers, vast bit depths, and diverse compression algorithms within a single file
  • Unmatched support for rich metadata including EXIF, IPTC, XMP, and custom ICC color profiles
Limitations
  • Produces exceptionally large file sizes compared to modern web formats
  • The 'x-tiff' legacy MIME string forces developers to write extra validation logic to prevent strict security filters from rejecting valid uploads
  • The format's immense complexity means that many lightweight parsers only implement a subset of the specification, sometimes failing to read obscure compressions (like CCITT or old JPEG-in-TIFF)

When to choose which format

PGM
Use PGM when…
  • Computer Vision and Machine Learning Pre-processing
  • Scientific and Medical Image Processing
  • Unix/Linux Command-Line Image Pipelines
TIFF
Use TIFF when…
  • Professional Print and Desktop Publishing
  • High-Resolution Archival Scanning
  • Master Copies of Digital Photography

More comparisons

PGM vs ACES → TIFF vs ACES → PGM vs APNG → TIFF vs APNG → PGM vs AVCI → TIFF vs AVCI → PGM vs AVCS → TIFF vs AVCS → PGM vs AVIF → TIFF vs AVIF → All comparisons →
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