Image MIME Reference
AOL-ART
AOL ART Image
image/x-jg
VS
JPEG XR Image Sequence (HEIF Container)
image/jxrs
JPEG-XR-Sequence
A complete technical comparison of AOL ART Image and JPEG XR Image Sequence (HEIF Container) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | AOL-ART | JPEG-XR-Sequence |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | Yes |
| Progressive Loading | Yes | Yes |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
AOL ART Image
image/x-jg
Extension
.art
Container
Johnson-Grace Proprietary
Compression
Proprietary Wavelet (Photos) / Proprietary Palette-based (Graphics)
Algorithm
Wavelet (similar to early JPEG 2000 concepts)Lossy DCT
Color Depth
8-bit (Indexed), 24-bit (RGB)
Developed by
Johnson-Grace Company (Acquired by AOL)
Released
1994
Magic Bytes
4A 47 03 00 or 4A 47 04 00
JPEG XR Image Sequence (HEIF Container)
image/jxrs
Extension
.jxrs
Container
HEIF / ISOBMFF (ISO/IEC 23008-12 / Annex F of ITU-T T.832)
Compression
Lossy / Lossless
Algorithm
JPEG XR (Lapped Biorthogonal Transform)
Color Depth
8-bit, 16-bit, 32-bit (Float)
Developed by
ISO/IEC JTC 1 / ITU-T
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 6A 78 72 53
Browser Support Comparison
| Browser | AOL-ART | JPEG-XR-Sequence |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
AOL-ART
AOL-ART Strengths
- Historically provided massive file size reductions (up to 3x smaller than JPEGs of the era) and highly optimized progressive rendering for 14.4k modems
- Enabled faster web browsing on the AOL network during the early days of the commercial internet
Limitations
- Completely proprietary, heavily patent-encumbered, and never officially reverse-engineered for the open-source community
- On-the-fly proxy compression ruined the visual fidelity of many 1990s websites for AOL users
- Virtually impossible to open on modern operating systems without installing niche, legacy image viewers
JPEG-XR-Sequence
JPEG-XR-Sequence Strengths
- Supports 32-bit floating point HDR color depths natively across an entire animation sequence
- Combines the advanced coding efficiencies of JPEG XR with the sequence timing and metadata framework of HEIF
- Shares frame data structures allowing for optimized storage of burst photography
Limitations
- Extremely rare format with essentially no mainstream software adoption
- Zero web browser support
- Overshadowed heavily by HEVC (HEIC sequences) and AV1 (AVIF sequences) which offer superior compression and broader hardware decoding support
When to choose which format
AOL-ART
Use AOL-ART when…
- Historical AOL Dial-up Web Browsing
- Legacy America Online Client Assets
- 1990s Internet Archival
JPEG-XR-Sequence
Use JPEG-XR-Sequence when…
- Experimental Animation Workflows
- HDR Burst Photography Archiving
- Specialized Medical & Scientific Imaging