Image MIME Reference
JPEG-LS
JPEG-LS
image/jls
VS
SealedMedia SoftSeal GIF
image/vnd.sealedmedia.softseal.gif
SoftSeal-GIF
A complete technical comparison of JPEG-LS and SealedMedia SoftSeal GIF — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | JPEG-LS | SoftSeal-GIF |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
JPEG-LS
image/jls
Extension
.jls.jl
Container
JPEG Bitstream
Compression
Lossless / Near-Lossless (Predictive Coding)
Algorithm
LOCO-I (Low Complexity Lossless Compression for Images)Golomb-Rice Coding
Color Depth
8-bit, 12-bit, 16-bit (Per Channel)
Developed by
Joint Photographic Experts Group (ISO/ITU-T) & HP Labs
Released
1999
Magic Bytes
FF D8 FF F7
SealedMedia SoftSeal GIF
image/vnd.sealedmedia.softseal.gif
Extension
.sgif.sealed-gif
Container
SealedMedia SoftSeal Wrapper
Compression
Encrypted Payload (LZW)
Algorithm
AES EncryptionLZW (Internal GIF payload)
Color Depth
Encrypted Payload (Historically up to 8-bit Indexed)
Developed by
SealedMedia (Acquired by Oracle Corporation)
Released
Late 1990s
Magic Bytes
Unknown (Proprietary SealedMedia Container)
Browser Support Comparison
| Browser | JPEG-LS | SoftSeal-GIF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
JPEG-LS
JPEG-LS Strengths
- Provides state-of-the-art lossless compression ratios for continuous-tone images, often outperforming Lossless JPEG and JPEG 2000
- Extremely fast and computationally inexpensive to encode/decode, requiring no complex floating-point math or DCTs
- Highly resilient in constrained hardware environments, making it ideal for medical equipment and deep-space probes (e.g., Mars rovers)
Limitations
- Zero native support in web browsers or standard consumer operating systems
- Lacks the advanced resolution scalability and progressive decoding features found in JPEG 2000
- Primarily relegated to niche enterprise sectors (healthcare/DICOM and aerospace) rather than consumer adoption
SoftSeal-GIF
SoftSeal-GIF Strengths
- Provided robust, persistent security that traveled with the file, ensuring images could not be leaked even if sent outside the corporate firewall
- Enabled dynamic revocation, meaning administrators could instantly kill access to a file globally
Limitations
- Completely proprietary and dependent on an active authentication server; if the DRM server dies, the image is permanently locked
- Zero support in modern operating systems, web browsers, or standard image editing suites without heavy enterprise client installations
- Often caused massive friction for legitimate end-users trying to view documents
When to choose which format
JPEG-LS
Use JPEG-LS when…
- Medical Imaging (DICOM Encapsulation)
- Space and Planetary Imaging (NASA/ESA)
- Industrial Machine Vision
- Scientific Archival Storage
SoftSeal-GIF
Use SoftSeal-GIF when…
- Enterprise Information Rights Management (IRM)
- Secure Distribution of Corporate Assets
- Revocable Medical, Legal, or Financial Imaging