Image MIME Reference
Generic-RAW
Digital Camera Raw (Generic Linux MIME)
image/x-dcraw
VS
RealNetworks RealFlash
image/vnd.rn-realflash
RealFlash
A complete technical comparison of Digital Camera Raw (Generic Linux MIME) and RealNetworks RealFlash — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Generic-RAW | RealFlash |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | Yes |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Digital Camera Raw (Generic Linux MIME)
image/x-dcraw
Extension
.raw
Container
Varies (Predominantly TIFF/EP)
Compression
Lossless / Uncompressed
Algorithm
Varies (Often Lossless JPEG ITU-T81 or uncompressed)
Color Depth
12-bit, 14-bit, 16-bit
Developed by
freedesktop.org (MIME mapping) / Dave Coffin (dcraw tool)
Released
1997
Magic Bytes
Varies by vendor format
RealNetworks RealFlash
image/vnd.rn-realflash
Extension
Container
RealMedia / SWF
Compression
Vector (Flash) / RealAudio Compression
Algorithm
Macromedia Vector CompressionDeflate (Zlib)
Color Depth
8-bit, 24-bit, 32-bit
Developed by
RealNetworks & Macromedia
Released
1997
Magic Bytes
46 57 53 (FWS - Standard Flash) or 2E 52 4D 46 (.RMF - RealMedia Container)
Browser Support Comparison
| Browser | Generic-RAW | RealFlash |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
Generic-RAW
Generic-RAW Strengths
- Provides a unified, highly useful catch-all MIME type for application developers who just need to know if a file is a raw image, rather than tracking 50+ individual camera extensions
- Deeply integrated into the Linux desktop ecosystem, ensuring file manager thumbnails work seamlessly via tools like ufraw-thumbnailer
Limitations
- Not an official IANA standard
- Can cause conflicts where standard TIFF files are misidentified as raw camera data by over-aggressive MIME sniffers
- The underlying 'dcraw' tool was abandoned by its creator in 2018 (though its successor, LibRaw, continues to maintain the ecosystem)
RealFlash
RealFlash Strengths
- Allowed complex, interactive vector animations to stream smoothly over 28.8k dial-up modems
- Perfectly synchronized streaming audio with timeline-based animations, which was revolutionary in 1997
Limitations
- Heavily reliant on proprietary browser plugins (RealPlayer), which were notoriously bloated
- Completely obsolete and unsupported on the modern web
- Tightly coupled server-client architecture required expensive RealServer licenses to host
When to choose which format
Generic-RAW
Use Generic-RAW when…
- Linux Desktop File Associations (GNOME/KDE)
- Thumbnail Generation for Raw Images (UFRaw/LibRaw)
- Server-side Image Processing Fallbacks
RealFlash
Use RealFlash when…
- Historical Dial-up Web Animation
- Late-1990s Interactive Music Videos
- Streaming Vector Graphics