Free webp to jpg
EN
Image MIME Reference
APNG

Animated Portable Network Graphics

image/vnd.mozilla.apng
VS

PWG Raster Format

image/pwg-raster
PWG-Raster

A complete technical comparison of Animated Portable Network Graphics and PWG Raster Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

APNG wins on browser support

Feature Support

Feature APNG PWG-Raster
Transparency (Alpha) Yes ✕ No
Animation Support Yes ✕ No
Progressive Loading Yes ✕ No
HDR Support ✕ No ✕ No
EXIF Metadata Yes ✕ No
ICC Color Profile Yes ✕ No
Animated Portable Network Graphics
image/vnd.mozilla.apng
Extension
.apng.png
Container PNG Chunk Stream
Compression Deflate (Lossless)
Algorithm
Deflate (zlib)
Color Depth 8-bit (Indexed), 24-bit (TrueColor), 32-bit (RGBA)
Developed by Mozilla Corporation (Stuart Parmenter & Vladimir Vukićević)
Released 2004
Magic Bytes
89 50 4E 47 0D 0A 1A 0A
Full APNG reference →
PWG Raster Format
image/pwg-raster
Extension
.pwg.ras
Container CUPS Raster v2 Container
Compression PackBits (Run-Length Encoding)
Algorithm
PackBits (Apple RLE variant)
Color Depth 1-bit (Monochrome/K), 8-bit (Grayscale), 24-bit (sRGB / Adobe RGB), 32-bit (CMYK)
Developed by IEEE-ISTO Printer Working Group (PWG)
Released 2011
Magic Bytes
52 61 53 32
Full PWG-Raster reference →

Browser Support Comparison

Browser APNG PWG-Raster
Chrome Chrome
✓ 59
 ✕
Firefox Firefox
✓ 3
 ✕
Safari Safari
✓ 8
 ✕
Edge Edge
✓ 79
 ✕
IE IE (Legacy)
✕ ✕
APNG

APNG Strengths

  • Supports 8-bit alpha transparency, completely solving the ugly 'white halo' problem inherent to GIFs
  • Gracefully degrades; viewers that do not support APNG will render a perfectly valid, static PNG of the first frame
  • Provides lossless compression that retains absolute pixel-perfect quality for UI elements and line art
Limitations
  • Because it relies on lossless Deflate compression, file sizes for complex, video-like animations can be massive compared to lossy formats like WebP or AVIF
  • Was initially rejected by the official PNG group, delaying its adoption for nearly a decade
  • Lacks native hardware decoding acceleration, unlike video-based animated formats (like MP4 or WebM)
PWG-Raster

PWG-Raster Strengths

  • The undisputed global standard for modern, driverless printing environments, eliminating the nightmare of installing manufacturer-specific print drivers
  • Extremely lightweight to decode on embedded hardware, requiring minimal RAM buffers on the printer side
  • Strict color space and resolution rules guarantee that the printed output will successfully process without syntax errors
Limitations
  • Generates massive file sizes and network payloads compared to vector-based formats like PDF or PostScript, as every page is fully rasterized at 300+ DPI before transmission
  • No support for native rendering in web browsers, image viewers, or graphic design software without specialized CUPS developer tools
  • Cannot store complex metadata, vector text, or layers

When to choose which format

APNG
Use APNG when…
  • High-Quality Web Animations
  • Stickers (Apple iMessage, LINE, Discord)
  • UI Loaders with Alpha Transparency
  • GIF Replacement
PWG-Raster
Use PWG-Raster when…
  • Driverless Network Printing (IPP Everywhere)
  • Apple AirPrint and Mopria Print Service Pipelines
  • CUPS (Common UNIX Printing System) Spooling

More comparisons

APNG vs ACES → PWG-Raster vs ACES → APNG vs AVCI → PWG-Raster vs AVCI → APNG vs AVCS → PWG-Raster vs AVCS → APNG vs AVIF → PWG-Raster vs AVIF → All comparisons →
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