Image MIME Reference
APNG
Animated Portable Network Graphics
image/vnd.mozilla.apng
VS
Digital Picture Exchange
image/dpx
DPX
A complete technical comparison of Animated Portable Network Graphics and Digital 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 | DPX |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | Yes | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | ✕ No | Yes |
| 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
Digital Picture Exchange
image/dpx
Extension
.dpx
Container
DPX (SMPTE ST 268)
Compression
Uncompressed / RLE (Rarely used)
Algorithm
Uncompressed
Color Depth
8-bit, 10-bit, 12-bit, 16-bit, 32-bit (Float)
Developed by
SMPTE (Society of Motion Picture and Television Engineers)
Released
1994
Magic Bytes
53 44 50 58 (Big-endian) / 58 50 44 53 (Little-endian)
Browser Support Comparison
| Browser | APNG | DPX |
|---|---|---|
Chrome
|
✓ 59
|
✕ |
Firefox
|
✓ 3
|
✕ |
Safari
|
✓ 8
|
✕ |
Edge
|
✓ 79
|
✕ |
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)
DPX
DPX Strengths
- Industry standard for transferring uncompressed, high-fidelity film and VFX data
- Rich industry-specific metadata including timecode, keykode, and film stock information
- Supports logarithmic color spaces (LogC, Cineon) to preserve the massive dynamic range of film negatives
Limitations
- Massive file sizes (e.g., a single 4K 10-bit frame is ~50MB, resulting in ~1.2GB per second at 24fps)
- Zero native support in web browsers or consumer OS image viewers
- Requires heavy-duty, fast storage infrastructure (RAID/NVMe) to playback in real-time
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
DPX
Use DPX when…
- Film Scanning
- Visual Effects (VFX)
- Digital Intermediate (DI)
- Color Grading
- Archival