Free webp to jpg
EN
Image MIME Reference
JNG

JPEG Network Graphics

image/x-jng
VS

PiCture eXchange

image/x-pcx
PCX

A complete technical comparison of JPEG Network Graphics and PiCture eXchange — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature JNG PCX
Transparency (Alpha) Yes ✕ No
Animation Support ✕ No ✕ No
Progressive Loading Yes ✕ No
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 →
PiCture eXchange
image/x-pcx
Extension
.pcx
Container ZSoft Proprietary Header (128 bytes)
Compression Run-Length Encoding (RLE)
Algorithm
ZSoft RLE
Color Depth 1-bit (Monochrome), 4-bit (16 colors), 8-bit (256 colors), 24-bit (True Color)
Developed by ZSoft Corporation
Released 1985
Magic Bytes
0A (followed by version, e.g., 0A 05 01 08)
Full PCX reference →

Browser Support Comparison

Browser JNG PCX
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  • Completely obsolete today, having been superseded by natively supported, superior formats like WebP, AVIF, and HEIC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
PCX

PCX Strengths

  • Incredibly simple RLE algorithm makes it very fast to decode, which was historically vital for early 3D video game engines
  • Retains crisp, lossless pixel data suitable for pixel art and interface assets
  • Well-documented and highly supported by older desktop publishing and image editing software
Limitations
  • Extremely inefficient compression by modern standards, producing large file sizes compared to PNG
  • Lacks modern imaging features such as alpha channel transparency, EXIF metadata, and color profiles
  • Zero support in web browsers; must be converted to PNG for web use

When to choose which format

JNG
Use JNG when…
  • Embedded frames in MNG animations
  • Historical web graphics requiring lossy compression with transparency
PCX
Use PCX when…
  • MS-DOS and Early Windows Graphics
  • 1990s Video Game Assets (Textures, UI)
  • Retro Computing Archival

More comparisons

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