Image MIME Reference
ACES
ACES Image Container File
image/aces
VS
Animated Portable Network Graphics
image/vnd.mozilla.apng
APNG
A complete technical comparison of ACES Image Container File and Animated Portable Network Graphics — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
APNG wins on browser support
Feature Support
| Feature | ACES | APNG |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | Yes |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
ACES Image Container File
image/aces
Extension
.exr
Container
OpenEXR (SMPTE ST 2065-4)
Compression
Lossless / Uncompressed
Algorithm
PIZZIPRLEB44Uncompressed
Color Depth
16-bit (Half-float), 32-bit (Float)
Developed by
Academy of Motion Picture Arts and Sciences (AMPAS) / SMPTE
Released
2013
Magic Bytes
76 2F 31 01
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
Browser Support Comparison
| Browser | ACES | APNG |
|---|---|---|
|
|
✕ |
✓ 59
|
|
|
✕ |
✓ 3
|
|
|
✕ |
✓ 8
|
|
|
✕ |
✓ 79
|
|
|
✕ | ✕ |
ACES
ACES Strengths
- Industry standard for high-end visual effects, compositing, and color grading
- Supports 16-bit half-float data, accurately capturing immense dynamic range without clipping
- Standardized by SMPTE (ST 2065-4) to guarantee universal color interoperability across different post-production facilities
Limitations
- Considerably larger file sizes than conventional consumer image formats
- Completely unsupported in web browsers and most standard desktop viewers
- Requires specialized compositing or color grading software to interpret and view the scene-linear data correctly
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)
When to choose which format
ACES
Use ACES when…
- Visual Effects (VFX)
- Digital Intermediate (DI)
- Color Grading
- Archival
APNG
Use APNG when…
- High-Quality Web Animations
- Stickers (Apple iMessage, LINE, Discord)
- UI Loaders with Alpha Transparency
- GIF Replacement