Image MIME Reference
MrSID
Multi-resolution Seamless Image Database
image/x-mrsid-image
VS
SealedMedia Portable Network Graphics
image/vnd.sealed.png
Sealed-PNG
A complete technical comparison of Multi-resolution Seamless Image Database and SealedMedia Portable Network Graphics — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | MrSID | Sealed-PNG |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Multi-resolution Seamless Image Database
image/x-mrsid-image
Extension
.sid
Container
Proprietary MrSID Container
Compression
Proprietary Wavelet (Lossy) / Proprietary Wavelet (Lossless)
Algorithm
Discrete Wavelet Transform (DWT)
Color Depth
8-bit (Grayscale), 24-bit (RGB), Multi-spectral (Multiple bands)
Developed by
Los Alamos National Laboratory / LizardTech (Extensis)
Released
1992
Magic Bytes
6D 73 69 64
SealedMedia Portable Network Graphics
image/vnd.sealed.png
Extension
.spng.sealed-png
Container
SealedMedia / Oracle IRM Wrapper
Compression
Encrypted Payload (Deflate)
Algorithm
AES EncryptionDeflate (Internal PNG payload)
Color Depth
Encrypted Payload
Developed by
SealedMedia (Acquired by Oracle Corporation)
Released
Late 1990s / Early 2000s
Magic Bytes
Unknown (Proprietary SealedMedia Container)
Browser Support Comparison
| Browser | MrSID | Sealed-PNG |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
MrSID
MrSID Strengths
- Incredible compression ratios enable multi-gigabyte geographical datasets to be stored on standard hard drives or transmitted easily
- Multi-resolution architecture means panning and zooming across a massive map is completely fluid, as the system decodes only the visible quadrant at the required zoom level
- Supports multi-spectral bands critical for remote sensing and agricultural GIS analysis
Limitations
- Deeply proprietary; creating or decoding MrSID files typically requires expensive commercial software or the proprietary Extensis DSDK
- Open-source geospatial libraries like GDAL require compiling against the proprietary SDK to legally enable MrSID support, causing licensing headaches for Linux server deployments
- Not natively viewable on the web without specialized geospatial map servers (like GeoServer or MapServer) tiling the image into PNGs or JPEGs on the fly
Sealed-PNG
Sealed-PNG Strengths
- Provided absolute control over intellectual property, allowing enterprise administrators to instantly revoke viewing rights of a local file globally
- Detailed audit trails tracked exactly who opened the image, when, and from what IP address
Limitations
- Completely proprietary and relies on a central authentication server; if the server goes offline, the image is permanently inaccessible
- No support in modern operating systems, web browsers, or standard image editing software without installing heavy enterprise DRM clients
- Oracle effectively deprecated the IRM product line, leaving legacy sealed documents difficult to recover
When to choose which format
MrSID
Use MrSID when…
- Geographic Information Systems (GIS)
- Satellite Imagery Archival
- Aerial Orthophotography Mosaics
Sealed-PNG
Use Sealed-PNG when…
- Enterprise Information Rights Management (IRM)
- Secure Corporate Intellectual Property Distribution
- Revocable Medical or Legal Imaging