Image MIME Reference
HEIF-Sequence
High Efficiency Image File Format Sequence
image/heif-sequence
VS
Kodak K25 Raw Image
image/x-kodak-k25
Kodak-K25
A complete technical comparison of High Efficiency Image File Format Sequence and Kodak K25 Raw Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | HEIF-Sequence | Kodak-K25 |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | ✕ No |
High Efficiency Image File Format Sequence
image/heif-sequence
Extension
.heifs.heif.hif
Container
HEIF / ISOBMFF (ISO/IEC 14496-12)
Compression
Lossy / Lossless
Algorithm
Codec Agnostic (HEVC, AVC, JPEG, AV1)
Color Depth
8-bit, 10-bit, 12-bit, 16-bit
Developed by
Moving Picture Experts Group (MPEG)
Released
2015
Magic Bytes
XX XX XX XX 66 74 79 70 6D 73 66 31
Kodak K25 Raw Image
image/x-kodak-k25
Extension
.k25
Container
Proprietary Kodak Raw (TIFF-based variant)
Compression
Uncompressed / Proprietary Lossless
Algorithm
Proprietary Kodak Compression
Color Depth
10-bit, 12-bit (Per Channel)
Developed by
Eastman Kodak Company
Released
1996
Magic Bytes
Varies (Often resembles TIFF header 49 49 2A 00 or requires proprietary parsing)
Browser Support Comparison
| Browser | HEIF-Sequence | Kodak-K25 |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
HEIF-Sequence
HEIF-Sequence Strengths
- Codec-agnostic container allows for extreme flexibility when storing multi-frame photographic data
- Maintains the space-saving benefits of ISOBMFF shared frame data blocks
- Excellent for archiving computational photography workloads like exposure brackets or focal stacks
Limitations
- Codec ambiguity means a decoder might be able to parse the container but fail to decode the underlying pixels
- Zero native web browser support
- Complex container structure requires specialized parsing libraries to extract individual frames
Kodak-K25
Kodak-K25 Strengths
- Historically significant format tied to the first digital camera to adopt CompactFlash memory
- Preserves original raw sensor data, allowing modern demosaicing algorithms (via LibRaw) to extract much better image quality than 1996-era software could
Limitations
- Completely obsolete and deeply proprietary, lacking modern raw format features found in DNG
- Cannot be natively viewed in web browsers or standard operating system image viewers without specialized decoders
- Subject to misidentification by automated MIME detection libraries due to structural similarities with standard TIFFs
When to choose which format
HEIF-Sequence
Use HEIF-Sequence when…
- Burst Photography
- Focal Stacking
- Exposure Bracketing
- Time-Lapse Data
Kodak-K25
Use Kodak-K25 when…
- Vintage Digital Photography Archival
- Kodak DC25 Camera Restorations
- Historical Imaging Research