Free webp to jpg
EN
Image MIME Reference
FLIF

Free Lossless Image Format

image/flif
VS

Portable Bitmap

image/x-portable-bitmap
PBM

A complete technical comparison of Free Lossless Image Format and Portable Bitmap — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature FLIF PBM
Transparency (Alpha) Yes ✕ No
Animation Support Yes ✕ No
Progressive Loading Yes ✕ No
HDR Support Yes ✕ No
EXIF Metadata Yes ✕ No
ICC Color Profile Yes ✕ No
Free Lossless Image Format
image/flif
Extension
.flif
Container FLIF Bitstream
Compression Lossless (MANIAC Entropy Coding)
Algorithm
MANIAC (Meta-Adaptive Near-zero Integer Arithmetic Coding)
Color Depth 1-bit to 16-bit (Per Channel), Grayscale, RGB, RGBA, CMYK
Developed by Jon Sneyers and Pieter Wuille (Cloudinary)
Released 2015
Magic Bytes
46 4C 49 46
Full FLIF reference →
Portable Bitmap
image/x-portable-bitmap
Extension
.pbm
Container Netpbm
Compression Uncompressed
Algorithm
None
Color Depth 1-bit (Monochrome)
Developed by Jef Poskanzer (Netpbm Project)
Released 1988
Magic Bytes
50 31 (ASCII) or 50 34 (Binary)
Full PBM reference →

Browser Support Comparison

Browser FLIF PBM
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
FLIF

FLIF Strengths

  • Achieves some of the highest lossless compression ratios ever developed for raster images
  • Incredible progressive decoding allows an image to be highly recognizable even after only 5% of the file has been downloaded
  • Supports animations and complex alpha channels losslessly
Limitations
  • Officially abandoned in favor of JPEG XL
  • Zero native support in web browsers or standard operating system previewers
  • Encoding speed can be significantly slower than standard PNG or WebP compression
PBM

PBM Strengths

  • Absolute structural simplicity allows parsers to be written from scratch with just a few lines of code
  • ASCII encoding allows manual editing and debugging directly within a standard text editor
  • Serves as a flawless, lossless intermediary for 1-bit raster data like scanned documents or barcodes
Limitations
  • Strictly limited to 1-bit monochrome images; cannot natively display shades of gray or color
  • Lack of compression results in extremely large file sizes, particularly when using the ASCII 'P1' encoding
  • No support for alpha transparency or modern metadata standards like EXIF

When to choose which format

FLIF
Use FLIF when…
  • Archival of Uncompressed Image Assets
  • Bandwidth-Constrained Progressive Image Loading (Historical)
  • Medical and Scientific Imaging Storage
PBM
Use PBM when…
  • Optical Character Recognition (OCR) Pre-processing
  • Unix/Linux Command-Line Image Pipelines
  • Academic Image Processing Teaching

More comparisons

FLIF vs ACES → PBM vs ACES → FLIF vs APNG → PBM vs APNG → FLIF vs AVCI → PBM vs AVCI → FLIF vs AVCS → PBM vs AVCS → FLIF vs AVIF → PBM vs AVIF → All comparisons →
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