Image MIME Reference
Apple-ICNS
Apple Icon Image
image/x-icns
VS
JPEG Stereo Image
image/x-jps
JPS
A complete technical comparison of Apple Icon Image and JPEG Stereo Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
JPS wins on browser support
Feature Support
| Feature | Apple-ICNS | JPS |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | Yes |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | Yes | Yes |
Apple Icon Image
image/x-icns
Extension
.icns
Container
Chunk-based (OSType Header)
Compression
Uncompressed (Legacy) / PNG (Modern) / JPEG 2000 (Modern)
Algorithm
NoneDeflate (via embedded PNG)Wavelet (via embedded JP2)
Color Depth
1-bit (Monochrome), 4-bit, 8-bit, 24-bit (RGB), 32-bit (RGBA)
Developed by
Apple Inc.
Released
2001
Magic Bytes
69 63 6E 73
JPEG Stereo Image
image/x-jps
Extension
.jps
Container
JPEG (JFIF/Exif)
Compression
Lossy (JPEG/DCT)
Algorithm
JPEG (Discrete Cosine Transform)
Color Depth
8-bit (Grayscale), 24-bit (RGB)
Developed by
Stereoscopic Community (Unofficial Standard)
Released
1990
Magic Bytes
FF D8 FF
Browser Support Comparison
| Browser | Apple-ICNS | JPS |
|---|---|---|
Chrome
|
✕ |
✓ 1
|
Firefox
|
✕ |
✓ 1
|
Safari
|
✕ |
✓ 1
|
Edge
|
✕ |
✓ 12
|
IE (Legacy)
|
✕ |
✓
|
Apple-ICNS
Apple-ICNS Strengths
- Seamlessly handles multi-resolution scaling on macOS, perfectly serving both standard and high-DPI (Retina) displays from a single asset
- Modern versions efficiently embed standard PNG files, making it much easier to parse the high-resolution layers than the legacy raw pixel formats
Limitations
- Strictly bound to the Apple ecosystem; completely useless natively on Windows, Linux, or the Web
- The internal chunking structure is notoriously messy, utilizing dozens of different undocumented, legacy OSType tags spanning 20+ years of Apple history
JPS
JPS Strengths
- 100% backward compatible with every standard 2D image viewer and web browser (which simply display the two halves side-by-side)
- Inherits JPEG's excellent lossy compression, resulting in small file sizes ideal for web transmission
- Extremely easy to generate programmatically by simply stitching two JPEG images side-by-side onto a wider canvas
Limitations
- Lack of a dedicated metadata standard means viewing software has to guess whether the layout is 'cross-eyed' (right eye left, left eye right) or 'parallel' (left eye left, right eye right), occasionally causing inverted depth
- Suffers from JPEG compression artifacts, which can break the stereoscopic illusion if compression noise differs between the left and right eyes
- Superseded in consumer electronics by the MPO (Multi-Picture Object) format, which stacks separate full-resolution JPEGs rather than squishing them side-by-side
When to choose which format
Apple-ICNS
Use Apple-ICNS when…
- macOS Application Bundles (.app)
- macOS Folder Customization
- Apple Disk Image (.dmg) Styling
JPS
Use JPS when…
- Stereoscopic 3D Photography
- Virtual Reality (VR) Image Galleries
- Cross-eye / Parallel Stereograms