Free webp to jpg
EN
Image MIME Reference
JNG

JPEG Network Graphics

image/x-jng
VS

North American Presentation Level Protocol Syntax

image/naplps
NAPLPS

A complete technical comparison of JPEG Network Graphics and North American Presentation Level Protocol Syntax — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature JNG NAPLPS
Transparency (Alpha) Yes ✕ No
Animation Support ✕ No Yes
Progressive Loading Yes Yes
HDR Support ✕ No ✕ No
EXIF Metadata Yes ✕ No
ICC Color Profile Yes ✕ No
JPEG Network Graphics
image/x-jng
Extension
.jng
Container PNG-style Chunk Structure (JHDR, JDAT, IDAT, IEND)
Compression Lossy (JPEG/DCT for color) / Lossless (Deflate for alpha mask)
Algorithm
JPEG (Discrete Cosine Transform)Deflate (LZ77)
Color Depth 8-bit, 12-bit, 24-bit (RGB), 32-bit (RGBA)
Developed by MNG Development Group (Glenn Randers-Pehrson et al.)
Released 2001
Magic Bytes
8B 4A 4E 47 0D 0A 1A 0A
Full JNG reference →
North American Presentation Level Protocol Syntax
image/naplps
Extension
.nap.naplps
Container NAPLPS Byte Stream
Compression Uncompressed (Tokenized ASCII Commands)
Algorithm
None (Coordinate encoding)
Color Depth 16-color palette (Indexed from larger color spaces)
Developed by ANSI / CSA (Based on Canadian CRC's Telidon)
Released 1983
Magic Bytes
1B (Variable / ESC sequences)
Full NAPLPS reference →

Browser Support Comparison

Browser JNG NAPLPS
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
JNG

JNG Strengths

  • Solved a massive technical hurdle in the early 2000s by combining high-compression lossy photographic data with crisp, 8-bit alpha transparency
  • Utilized the highly robust, extensible chunk-based architecture of the PNG format
  • Provided an excellent, bandwidth-saving alternative to massive 32-bit transparent PNGs for web design
Limitations
  • Failed to achieve critical mass; browser vendors largely abandoned the MNG/JNG standard due to implementation complexity
  • Completely obsolete today, having been superseded by natively supported, superior formats like WebP, AVIF, and HEIC
  • Decoding requires a hybrid engine that can parse PNG chunks while simultaneously decoding a JPEG stream and a Deflate stream, complicating software support
NAPLPS

NAPLPS Strengths

  • Extremely bandwidth-efficient, enabling colorful graphical interfaces over early 300 baud dial-up connections
  • Resolution-independent vector scaling allowed the exact same file to be displayed accurately on varied early PC monitors and television sets
Limitations
  • Completely obsolete and unsupported by modern web technologies
  • Relies heavily on stateful parsing and terminal emulators rather than straightforward file decoding
  • Easily misidentified by MIME sniffers as plain text or generic binary streams due to the lack of a standardized file header

When to choose which format

JNG
Use JNG when…
  • Embedded frames in MNG animations
  • Historical web graphics requiring lossy compression with transparency
NAPLPS
Use NAPLPS when…
  • 1980s Videotex Services
  • Prodigy Online Service Graphics
  • Historical BBS Terminal Graphics
  • Legacy Teletext Broadcasts

More comparisons

JNG vs ACES → NAPLPS vs ACES → JNG vs APNG → NAPLPS vs APNG → JNG vs AVCI → NAPLPS vs AVCI → JNG vs AVCS → NAPLPS vs AVCS → JNG vs AVIF → NAPLPS vs AVIF → All comparisons →
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