Free webp to jpg
EN
Image MIME Reference
APNG

Animated Portable Network Graphics

image/vnd.mozilla.apng
VS

PiCture eXchange

image/x-pcx
PCX

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

APNG wins on browser support

Feature Support

Feature APNG PCX
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 →
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 APNG PCX
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)
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

APNG
Use APNG when…
  • High-Quality Web Animations
  • Stickers (Apple iMessage, LINE, Discord)
  • UI Loaders with Alpha Transparency
  • GIF Replacement
PCX
Use PCX when…
  • MS-DOS and Early Windows Graphics
  • 1990s Video Game Assets (Textures, UI)
  • Retro Computing Archival

More comparisons

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