Free webp to jpg
EN
Image MIME Reference
APNG

Animated Portable Network Graphics

image/vnd.mozilla.apng
VS

Corel Metafile Exchange

image/x-cmx
Corel-CMX

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

APNG wins on browser support

Feature Support

Feature APNG Corel-CMX
Transparency (Alpha) Yes Yes
Animation Support Yes ✕ No
Progressive Loading Yes ✕ No
HDR Support ✕ No ✕ No
EXIF Metadata Yes ✕ No
ICC Color Profile Yes Yes
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 →
Corel Metafile Exchange
image/x-cmx
Extension
.cmx
Container RIFF (Resource Interchange File Format)
Compression Uncompressed Vector Commands / Embedded Raster Compression (Optional)
Algorithm
None (Vector)
Color Depth Vector Data, Supports embedded bitmaps
Developed by Corel Corporation
Released Mid-1990s
Magic Bytes
52 49 46 46 (skip 4) 43 4D 58 31
Full Corel-CMX reference →

Browser Support Comparison

Browser APNG Corel-CMX
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)
Corel-CMX

Corel-CMX Strengths

  • Preserves rich vector attributes and layer groupings native to the Corel drawing engine better than standard WMF files
  • Significantly smaller footprint than full CDR project files, making it excellent for early CD-ROM clip art distribution
  • Maintains decent support in the open-source community thanks to libraries like libcdr
Limitations
  • Proprietary format strictly tied to Corel's ecosystem, often causing compatibility issues with Adobe software
  • Zero support in web browsers; must be converted to SVG for modern web usage
  • Largely obsolete for modern workflows, superseded by PDF and SVG

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
Corel-CMX
Use Corel-CMX when…
  • Legacy CorelDRAW Clip Art Collections
  • Vector Graphic Exchange within Corel Suite
  • Historical Desktop Publishing Assets

More comparisons

APNG vs ACES → Corel-CMX vs ACES → APNG vs AVCI → Corel-CMX vs AVCI → APNG vs AVCS → Corel-CMX vs AVCS → APNG vs AVIF → Corel-CMX vs AVIF → All comparisons →
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